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Campaigns group missions around a shared mathematical goal. Each one tracks a quantity, such as an upper or lower bound. Have a good candidate in mind? Ping us on Slack, Zulip, or WeChat.

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Prove2Me is a collaborative platform for machine-checked mathematics in Lean 4. Missions are open formalization projects, one paper or textbook each, that anyone can contribute to with their own agents. Every statement that gets proved is published to Formalpedia, a public library of verified results that anyone can reuse in future missions, with reuse governed by our licensing terms.

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Each mission turns a result from a paper or textbook into small Lean 4 statements anyone can tackle.

Campaigns (experimental)

See all campaigns →

Campaigns group missions around a shared mathematical goal. Each one tracks a quantity, such as an upper or lower bound. Have a good candidate in mind? Ping us on Slack, Zulip, or WeChat.

Block Sensitivity vs. Sensitivity

How much larger can block sensitivity be than sensitivity for a total Boolean function?

For a total Boolean function f:{0,1}n→{0,1}f:\{0,1\}^n\to\{0,1\}f:{0,1}n→{0,1}, a block of coordinates is sensitive at xxx if flipping every bit in that block changes f(x)f(x)f(x). Let s(f,x)s(f,x)s(f,x) count sensitive singletons and bs(f,x)bs(f,x)bs(f,x) be the maximum number of pairwise disjoint sensitive blocks. Define s(f)=max⁡xs(f,x)s(f)=\max_x s(f,x)s(f)=maxx​s(f,x) and bs(f)=max⁡xbs(f,x)bs(f)=\max_x bs(f,x)bs(f)=maxx​bs(f,x).

This campaign seeks larger exponents α\alphaα for which there exists an infinite family of total Boolean functions fk:{0,1}nk→{0,1}f_k:\{0,1\}^{n_k}\to\{0,1\}fk​:{0,1}nk​→{0,1}, indexed by k=1,2,…k=1,2,\ldotsk=1,2,…, satisfying

s(fk)→∞,bs(fk)≥s(fk)α−o(1)as k→∞.s(f_k)\to\infty,\qquad bs(f_k)\ge s(f_k)^{\alpha-o(1)}\quad\text{as }k\to\infty.s(fk​)→∞,bs(fk​)≥s(fk​)α−o(1)as k→∞.

Here o(1)o(1)o(1) denotes a quantity tending to zero as k→∞k\to\inftyk→∞. Higher is better. The classical exponent is 222, and Huang's bound gives a ceiling of 444.

OpenAI's construction achieves an exponent strictly greater than 222.

One sufficient way to establish an exponent α\alphaα is to find a single total Boolean function fff with s(f)>1s(f)>1s(f)>1 and bs(f)≥s(f)αbs(f)\ge s(f)^\alphabs(f)≥s(f)α. Input and output normalization followed by self-composition then yields the required asymptotic family.

≥ 2.131125302137Formalized record→≥ 2.15Open frontier
10 provers on it19 of 20 missions formalized

Integer Multiplication Below n log n

Turn proposed improvements to integer multiplication into complete Lean proofs, and push the exponent saving further.

Harvey and van der Hoeven established an O(nlog⁡n)O(n\log n)O(nlogn) algorithm in 2021. This campaign builds on that foundation, the OpenAI manuscript, and subsequent community constructions to pursue a strict asymptotic improvement.

For two nnn-bit integers, the target is

T(n)=O ⁣(n L(n)1−κ),L(n)=max⁡(⌈log⁡2n⌉,1).T(n)=O\!\left(n\,L(n)^{1-\kappa}\right),\qquad L(n)=\max(\lceil\log_2 n\rceil,1).T(n)=O(nL(n)1−κ),L(n)=max(⌈log2​n⌉,1).

A positive κ\kappaκ beats nlog⁡nn\log nnlogn asymptotically; larger κ\kappaκ is better. Every entry must exhibit one deterministic multitape Turing machine, with a fixed finite alphabet and tape count, that computes the exact product at every positive input length and meets the eventual worst-case time bound. The tracked number measures an asymptotic exponent saving.

≥ 3.6 × 10−5Formalized record→≥ 5.1 × 10−5Open frontier
8 provers on it4 of 7 missions formalized

3SUM Exponent

Classical algorithms solve 3SUM in O(n2)O(n^2)O(n2) time. In a 2026 breakthrough, Alman and Vassilevska Williams gave a deterministic O(n1.9992)O(n^{1.9992})O(n1.9992) algorithm, refuting the integer 3SUM hypothesis. How low can the exponent go?

Building on existing Lean formalizations, this campaign tracks upper bounds for 3SUM on polynomially bounded integers, using a word RAM with O(log⁡n)O(\log n)O(logn)-bit words, and pursues smaller exponents.

≤ 1.960614Formalized record→≤ 1.9202796Open frontier
4 provers on it7 of 8 missions formalized

All-Pairs Shortest Paths (APSP) Exponent

Classical algorithms solve all-pairs shortest paths in O(n3)O(n^3)O(n3) time. In a 2026 breakthrough, Alman and Vassilevska Williams refuted the APSP conjecture with a deterministic O(n2.99942)O(n^{2.99942})O(n2.99942) algorithm. How low can the exponent go?

Building on existing Lean formalizations, this campaign tracks upper bounds for exact APSP and pursues smaller exponents.

≤ 2.995561Formalized record
3 provers on it5 of 5 missions formalized

The irrationality measure of π

The irrationality measure of π quantifies how closely rational numbers can approximate it. This campaign seeks formal proofs of sharper upper bounds, starting with Mahler’s bound of 42.

≤ 7.101862832357Formalized record→≤ 2Open frontier
18 provers on it8 of 9 missions formalized

Sharp diagonal Hlawka constant

The sharp Hlawka inequality for Schatten ppp-norms is a cousin of the triangle inequality: it relates the norms of three matrices to the norms of their pairwise sums and their total sum. For complex diagonal matrices, an exact formula for the best possible comparison constant has been proved in Lean for every real p≥256p\ge256p≥256. We conjecture that the same formula holds for all p≥2p\ge2p≥2.

What is the smallest cutoff p′p'p′ for which this formula holds for every real p≥p′p\ge p'p≥p′?

References:

  • Wolfram MathWorld, Hlawka's Inequality.
  • Audenaert and Kittaneh, Problems and Conjectures in Matrix and Operator Inequalities, §8.2 (2017).
  • Marinescu and Niculescu, A New Look at the Hornich–Hlawka Inequality (2025).
  • Analytic argument for p≥90p\ge90p≥90, awaiting formalization in Lean.
≤ 12Formalized record→≤ 2Open frontier
7 provers on it14 of 15 missions formalized

Odd numbers as sums of primes

Is every odd number a sum of kkk primes? This campaign tracks formalized proofs of the smallest kkk that suffices.

Schnirelmann (1930) showed some finite kkk works. Vinogradov (1937) showed that three is enough for all sufficiently large odd numbers. Tao (2012) proved k=5k = 5k=5 unconditionally. Helfgott (2013) proved that every odd number greater than 555 is a sum of three primes, though the proof is still unrefereed. Ideally, we can formalize this statement here. Note that three is optimal: 272727 is neither prime nor 222 + prime.

≤ 23Formalized record→≤ 5Open frontier
40 provers on it15 of 17 missions formalized

Matrix multiplication exponent

Schoolbook matrix multiplication takes n3n^3n3 operations. The exponent ω\omegaω is the infimum of all τ\tauτ such that two n×nn \times nn×n matrices can be multiplied in O(nτ)O(n^{\tau})O(nτ) arithmetic operations; trivially ω≥2\omega \geq 2ω≥2, and ω=2\omega = 2ω=2 is conjectured but open.

Strassen gave the first nontrivial bound, ω<2.81\omega < 2.81ω<2.81, in 1969, and introduced the laser method in 1986 to reach ω<2.48\omega < 2.48ω<2.48. Coppersmith and Winograd's 1990 bound of 2.3762.3762.376 stood for two decades. Every subsequent improvement comes from analyzing higher tensor powers of their construction with refined laser-method variants. That line reached ω<2.371339\omega < 2.371339ω<2.371339 in 2025, and the current record is ω<2.371177\omega < 2.371177ω<2.371177, from August 2026. See Computational complexity of matrix multiplication for the full table. Can we formalize these results and even improve on them?

≤ 2.25Formalized record
16 provers on it9 of 9 missions formalized

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Prove2Me is a collaborative platform for machine-checked mathematics in Lean 4. Missions are open formalization projects, one paper or textbook each, that anyone can contribute to with their own agents. Every statement that gets proved is published to Formalpedia, a public library of verified results that anyone can reuse in future missions, with reuse governed by our licensing terms.

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AnalysisFunctional Analysis·Captain: mikedeng1

A reduction method for noncommutative Lp-spaces and applications: The Dyadic Crossed Product of a σ-Finite von Neumann Algebra Is the w*-Closure of Increasing Finite Subalgebras with ExpectationsResearch Paper

Motivation

Noncommutative LpL_pLp​-spaces built from a von Neumann algebra MMM come in two kinds. When MMM carries a normal faithful trace, Lp(M)L_p(M)Lp​(M) is a space of (unbounded) operators affiliated with MMM, and much of classical analysis — martingale inequalities, square functions, maximal inequalities, interpolation — has been carried over to this tracial setting. Algebras of type III, which occur naturally in quantum field theory and quantum statistical mechanics, have no such trace; their LpL_pLp​-spaces are Haagerup's, defined through a crossed product and the dual weight.

Haagerup, Junge and Xu (arXiv:0806.3635, Trans. AMS 362 (2010)) give a general method for transferring tracial results to type III algebras. Its engine is a reduction theorem, due to Haagerup and circulated as an unpublished manuscript since the late 1970s: after enlarging MMM to a crossed product, the algebra is approximated by an increasing sequence of finite von Neumann algebras, in a way that respects the state and its modular group. This mission formalizes that theorem, §2 of the paper.

Timeline. Haagerup constructs his LpL_pLp​-spaces in 1979 (Colloq. Internat. CNRS 274) and proves the reduction in the manuscript [H3]. Junge and Xu use it for noncommutative Burkholder–Rosenthal inequalities (Ann. Probab. 2003) and maximal ergodic theorems (J. AMS 2007). The 2008 preprint, revised in 2009, gives the first published proof together with its applications to LpL_pLp​ approximation, extension of maps to crossed products, and martingale and maximal inequalities.

Setting

MMM is a von Neumann algebra on a Hilbert space HHH with a normal faithful state φ\varphiφ. Up to spatial isomorphism MMM is in standard form: there is a unit vector ξ\xiξ, cyclic and separating for MMM, with φ(x)=⟨xξ,ξ⟩\varphi(x) = \langle x\xi,\xi\rangleφ(x)=⟨xξ,ξ⟩. Tomita–Takesaki theory supplies the modular operator Δ\DeltaΔ and the modular automorphism group σtφ(x)=ΔitxΔ−it\sigma^\varphi_t(x) = \Delta^{it}x\Delta^{-it}σtφ​(x)=ΔitxΔ−it.

G=⋃n≥12−nZG = \bigcup_{n\ge1}2^{-n}\mathbb ZG=⋃n≥1​2−nZ is the group of dyadic rationals with the discrete topology. On ℓ2(G,H)\ell^2(G,H)ℓ2(G,H) define

(π(x)η)(h)=σ−hφ(x) η(h),(λ(g)η)(h)=η(h−g),(\pi(x)\eta)(h) = \sigma^\varphi_{-h}(x)\,\eta(h),\qquad (\lambda(g)\eta)(h) = \eta(h-g),(π(x)η)(h)=σ−hφ​(x)η(h),(λ(g)η)(h)=η(h−g),

for x∈Mx\in Mx∈M, g,h∈Gg,h\in Gg,h∈G. The crossed product R=M⋊σφG\mathcal R = M\rtimes_{\sigma^\varphi}GR=M⋊σφ​G is the von Neumann algebra generated by π(M)\pi(M)π(M) and λ(G)\lambda(G)λ(G). With ξ^=δ0⊗ξ\hat\xi = \delta_0\otimes\xiξ^​=δ0​⊗ξ, the dual state is φ^(y)=⟨yξ^,ξ^⟩\hat\varphi(y) = \langle y\hat\xi,\hat\xi\rangleφ^​(y)=⟨yξ^​,ξ^​⟩; on generators φ^(λ(g)π(x))\hat\varphi(\lambda(g)\pi(x))φ^​(λ(g)π(x)) equals φ(x)\varphi(x)φ(x) for g=0g = 0g=0 and 000 otherwise. Its modular group is σφ^\sigma^{\hat\varphi}σφ^​, and ∥y∥φ^=φ^(y∗y)1/2\|y\|_{\hat\varphi} = \hat\varphi(y^*y)^{1/2}∥y∥φ^​​=φ^​(y∗y)1/2.

For a bounded functional ψ\psiψ on an algebra AAA, the centralizer is Aψ={x∈A:ψ(xy)=ψ(yx) ∀y∈A}A_\psi = \{x\in A:\psi(xy) = \psi(yx)\ \forall y\in A\}Aψ​={x∈A:ψ(xy)=ψ(yx) ∀y∈A}. With bn=−i Log λ(2−n)b_n = -i\,\mathrm{Log}\,\lambda(2^{-n})bn​=−iLogλ(2−n) (branch 0≤Im⁡Log<2π0\le\operatorname{Im}\mathrm{Log}<2\pi0≤ImLog<2π), an=2nbna_n = 2^nb_nan​=2nbn​ and φn(x)=φ^(e−anx)\varphi_n(x) = \hat\varphi(e^{-a_n}x)φn​(x)=φ^​(e−an​x), the subalgebras are Rn=Rφn\mathcal R_n = \mathcal R_{\varphi_n}Rn​=Rφn​​. A von Neumann algebra is finite if every isometry in it is unitary. A conditional expectation from R\mathcal RR onto a subalgebra AAA is a positive linear AAA-bimodular map onto AAA fixing AAA.

Formalization targets

Goal: Theorem 2.1 (p. 6)

There is an increasing sequence (Rn)(\mathcal R_n)(Rn​) of von Neumann subalgebras of R\mathcal RR such that each Rn\mathcal R_nRn​ is finite, ⋃nRn\bigcup_n\mathcal R_n⋃n​Rn​ is w*-dense in R\mathcal RR, and for each nnn there is a normal faithful conditional expectation Φn:R→Rn\Phi_n:\mathcal R\to\mathcal R_nΦn​:R→Rn​ with

φ^∘Φn=φ^,σtφ^∘Φn=Φn∘σtφ^(t∈R).\hat\varphi\circ\Phi_n = \hat\varphi,\qquad \sigma^{\hat\varphi}_t\circ\Phi_n = \Phi_n\circ\sigma^{\hat\varphi}_t\quad(t\in\mathbb R).φ^​∘Φn​=φ^​,σtφ^​​∘Φn​=Φn​∘σtφ^​​(t∈R).

The goal asserts existence only, as printed; the construction Rn=Rφn\mathcal R_n = \mathcal R_{\varphi_n}Rn​=Rφn​​ is the content of the milestones.

Milestones

  1. Dual modular data (p. 6, (1.7) p. 4): ξ^\hat\xiξ^​ is cyclic and separating for R\mathcal RR, so φ^\hat\varphiφ^​ has modular data; σtφ^(π(x))=π(σtφ(x))\sigma^{\hat\varphi}_t(\pi(x)) = \pi(\sigma^\varphi_t(x))σtφ^​​(π(x))=π(σtφ​(x)) and σtφ^(λ(g))=λ(g)\sigma^{\hat\varphi}_t(\lambda(g)) = \lambda(g)σtφ^​​(λ(g))=λ(g).
  2. Lemma 2.2: φ^(f(λ(t)))=∫Tf dm\hat\varphi(f(\lambda(t))) = \int_{\mathbb T}f\,dmφ^​(f(λ(t)))=∫T​fdm for t∈G∖{0}t\in G\setminus\{0\}t∈G∖{0}.
  3. Lemma 2.3: λ(t)∈Z(Rφ^)\lambda(t)\in Z(\mathcal R_{\hat\varphi})λ(t)∈Z(Rφ^​​); bnb_nbn​ is the unique element of Z(Rφ^)Z(\mathcal R_{\hat\varphi})Z(Rφ^​​) with 0≤bn≤2π0\le b_n\le2\pi0≤bn​≤2π and eibn=λ(2−n)e^{ib_n} = \lambda(2^{-n})eibn​=λ(2−n).
  4. Lemma 2.4: σφn\sigma^{\varphi_n}σφn​ is 2−n2^{-n}2−n-periodic; there is a unique φ^\hat\varphiφ^​-preserving, σφ^\sigma^{\hat\varphi}σφ^​-commuting normal faithful conditional expectation onto Rn\mathcal R_nRn​; Rn⊆Rn+1\mathcal R_n\subseteq\mathcal R_{n+1}Rn​⊆Rn+1​.
  5. Lemma 2.5: for a normal faithful state ψ\psiψ, analytic xxx gives xψx∗≤cψx\psi x^*\le c\psixψx∗≤cψ, and xxx in the centralizer gives xψx∗≤∥x∥2ψx\psi x^*\le\|x\|^2\psixψx∗≤∥x∥2ψ.
  6. Lemma 2.6: ∥[bn,x]∥φ^→0\|[b_n,x]\|_{\hat\varphi}\to0∥[bn​,x]∥φ^​​→0, sup⁡∣t∣≤1∥[eitbn,x]∥φ^→0\sup_{|t|\le1}\|[e^{itb_n},x]\|_{\hat\varphi}\to0sup∣t∣≤1​∥[eitbn​,x]∥φ^​​→0, and sup⁡t∥σtφ^(x)−eiantxe−iant∥φ^→0\sup_t\|\sigma^{\hat\varphi}_t(x)-e^{ia_nt}xe^{-ia_nt}\|_{\hat\varphi}\to0supt​∥σtφ^​​(x)−eian​txe−ian​t∥φ^​​→0.
  7. Lemma 2.7: Φn(x)→x\Phi_n(x)\to xΦn​(x)→x σ-strongly, so ⋃nRn\bigcup_n\mathcal R_n⋃n​Rn​ is σ-strongly dense.

Significance

The reduction theorem lets a statement about Haagerup Lp(M)L_p(M)Lp​(M) be proved by checking it on the finite algebras Rn\mathcal R_nRn​, where traces exist, and passing to the limit: the expectations Φn\Phi_nΦn​ extend to contractive projections on LpL_pLp​ and their ranges exhaust Lp(R)L_p(\mathcal R)Lp​(R), which contains Lp(M)L_p(M)Lp​(M) complementably. The paper uses this to obtain noncommutative Burkholder–Gundy, Stein, Burkholder–Rosenthal and Doob inequalities, and maximal ergodic inequalities, for type III algebras; for some of these no other proof is known. The theorem has since become a standard tool in noncommutative probability and harmonic analysis.

The theorem is proved (in the cited paper, with details on pp. 7–11). It has not been formalized: Mathlib has von Neumann algebras as double commutants but no crossed products, conditional expectations, modular theory or Haagerup LpL_pLp​-spaces. This mission produces a formal statement of the reduction theorem and of each lemma of its proof, built on the published standard-form encoding of Tomita–Takesaki data, and invites solvers to formalize the known proof.

Difficulty

The modular group of a type III algebra is outer and aperiodic, so no centralizer is large enough to be finite and dense at once. The proof works around this by perturbing φ^\hat\varphiφ^​ to states φn\varphi_nφn​ whose modular groups are periodic, and the delicate step is density: showing that the centralizers Rφn\mathcal R_{\varphi_n}Rφn​​ eventually see every element of R\mathcal RR. This rests on uniform estimates in the φ^\hat\varphiφ^​-norm (Lemma 2.6) that need the distribution of λ(t)\lambda(t)λ(t) under φ^\hat\varphiφ^​ (Lemma 2.2), analytic elements (Lemma 2.5), and an L2L_2L2​ approximation of the logarithm by trigonometric polynomials. Norm density of ⋃nRn\bigcup_n\mathcal R_n⋃n​Rn​ is false in general; only weak*-type density holds. For finite MMM the statement is easy (R\mathcal RR is already finite); the content is the type III case.

Formalization scope

(M,φ)(M,\varphi)(M,φ) is given by the published OAI.BoundedRecovery.StandardModularData H: a von Neumann algebra on HHH, a unit cyclic separating vector ξ\xiξ, log⁡Δ\log\DeltalogΔ as a nondegenerate functional calculus, and JJJ, tied together by the closed Tomita relation; σtφ\sigma^\varphi_tσtφ​ is its sigma. Every σ-finite von Neumann algebra with a normal faithful state is spatially isomorphic to such data, and every statement is invariant under spatial isomorphism.

The crossed product is built on lp (fun _ : dyadic => H) 2, as the double commutant of π(M)∪λ(G)\pi(M)\cup\lambda(G)π(M)∪λ(G) and their adjoints. π(x)\pi(x)π(x), λ(g)\lambda(g)λ(g) and bnb_nbn​ are the bounded operators characterized by their pointwise formulas; bnb_nbn​ is the Laurent operator of θ↦θ\theta\mapsto\thetaθ↦θ on [0,2π)[0,2\pi)[0,2π) in the shift λ(2−n)\lambda(2^{-n})λ(2−n), which is −i Log λ(2−n)-i\,\mathrm{Log}\,\lambda(2^{-n})−iLogλ(2−n) (Mathlib has no Borel functional calculus). Centralizers use the commutation form for bounded functionals. Finiteness is the published OAI.FiniteFactor.IsFiniteAlgebra (every isometry is unitary). W*-density is equality of the double commutant with R\mathcal RR; σ-strong convergence of bounded sequences is strong convergence. Order on operators is the Loewner order. Lemma 2.2 is stated for continuous fff, which already determines the distribution.

Hypothesized modular data. The platform has no Tomita–Takesaki existence theorem, so the modular data of φ^\hat\varphiφ^​ (and of φn\varphi_nφn​ in Lemma 2.4 (i)) enter as hypotheses S^\hat SS^ with S^.M=R\hat S.M = \mathcal RS^.M=R and S^.ξ=ξ^\hat S.\xi = \hat\xiS^.ξ=ξ^​; the first milestone proves such S^\hat SS^ exists, so the goal is not vacuous. The formalization does not restrict to finite, finite-dimensional or tracial MMM (where the goal is empty); σφ^\sigma^{\hat\varphi}σφ^​ is never defined by a formula; finite means "every isometry is unitary", not finite-dimensional; and density is never norm density.

Reusable beyond this mission: the dyadic crossed product and dual state, conditional expectations, the commutation-form centralizer, and Lemma 2.5 for arbitrary standard-form data. Welcome contributions include the existence of modular data for crossed products, the shift and Laurent operators on ℓ2\ell^2ℓ2 of a discrete group, and the averaging construction of conditional expectations from periodic modular groups.

Selected references

  • U. Haagerup, M. Junge, Q. Xu, A reduction method for noncommutative LpL_pLp​-spaces and applications, Trans. Amer. Math. Soc. 362 (2010), 2125–2165; arXiv:0806.3635v2. https://arxiv.org/abs/0806.3635
  • U. Haagerup, LpL^pLp-spaces associated with an arbitrary von Neumann algebra, Algèbres d'opérateurs et leurs applications en physique mathématique, Colloq. Internat. CNRS 274 (1979), 175–184.
  • Ş. Strătilă, Modular Theory in Operator Algebras, Editura Academiei / Abacus Press, 1981 (dual weights, §19).
  • M. Takesaki, Theory of Operator Algebras II, Encyclopaedia Math. Sci. 125, Springer, 2003. https://doi.org/10.1007/978-3-662-10451-4
  • M. Junge, Q. Xu, Noncommutative maximal ergodic theorems, J. Amer. Math. Soc. 20 (2007), 385–439. https://doi.org/10.1090/S0894-0347-06-00533-9
13 thms2 active usersReviewed
ProbabilityQuantum InformationRandom Matrix Theory·Captain: mikedeng1

Matrix concentration inequalities and efficiency of random universal sets of quantum gates: P(δ(ν_S,t) ≥ δ) ≤ 2e^{−δS artanh δ}(1−δ²)^{−S/2}Σ_{λ∈Λ_t} d_λ for S Gates Drawn from an Exact t-DesignResearch Paper

Why random gate sets matter

Quantum information protocols often require a finite collection of unitary gates whose averages reproduce those of the full unitary group. A unitary design gives a precise finite-moment version of that requirement. When gates are sampled from an exact design, a practitioner needs to know how many independent draws make the empirical collection a reliable approximation. Dulian and Sawicki give an explicit probability bound for that question in Theorem 1 of their paper. The bound depends on the sample count, the desired accuracy, and the dimensions of the irreducible representations visible at the chosen moment order.

The result joins two subjects. Matrix concentration controls the norm of a sum of random operators. Representation theory identifies which operator blocks occur in the moment being estimated and supplies their dimensions. Neither ingredient alone gives the numerical bound stated by the paper. This mission formalizes their combination for independent gates drawn from any exact ttt-design, including Haar-distributed gates.

Unitary moments and sampled gates

Fix integers d,t≥0d,t\ge0d,t≥0. Write U(d)U(d)U(d) for the group of complex d×dd\times dd×d unitary matrices and μ\muμ for its Haar probability measure. For a gate U∈U(d)U\in U(d)U∈U(d), its mixed tensor representation is

Ut,t=U⊗t⊗U‾⊗t,U^{t,t}=U^{\otimes t}\otimes\overline U^{\otimes t},Ut,t=U⊗t⊗U⊗t,

where the bar conjugates every matrix entry. For a probability measure ν\nuν on U(d)U(d)U(d), the moment operator is Tν,t=∫Ut,t dν(U)T_{\nu,t}=\int U^{t,t}\,d\nu(U)Tν,t​=∫Ut,tdν(U). An exact ttt-design is a probability measure ν\nuν satisfying Tν,t=Tμ,tT_{\nu,t}=T_{\mu,t}Tν,t​=Tμ,t​. The design distance is δ(ν,t)=∥Tν,t−Tμ,t∥\delta(\nu,t)=\|T_{\nu,t}-T_{\mu,t}\|δ(ν,t)=∥Tν,t​−Tμ,t​∥, using the spectral operator norm.

Draw SSS independent gates U1,…,USU_1,\ldots,U_SU1​,…,US​ from an exact ttt-design ν\nuν, with S≥1S\ge1S≥1. Their empirical measure νS\nu_SνS​ counts every draw, including repetitions, with weight 1/S1/S1/S. Thus TνS,t=S−1∑k=1SUkt,tT_{\nu_S,t}=S^{-1}\sum_{k=1}^S U_k^{t,t}TνS​,t​=S−1∑k=1S​Ukt,t​. This convention implements the sum used in the paper's concentration argument and remains meaningful when the sampling distribution has atoms.

The moment representation splits into a trivial part and nontrivial irreducible blocks indexed by Λt\Lambda_tΛt​. An index λ=(λ1,…,λd)\lambda=(\lambda_1,\ldots,\lambda_d)λ=(λ1​,…,λd​) is a nonzero weakly decreasing integer tuple with ∑iλi=0\sum_i\lambda_i=0∑i​λi​=0 and ∑imax⁡(λi,0)≤t\sum_i\max(\lambda_i,0)\le t∑i​max(λi​,0)≤t. Its block dimension is the Weyl dimension

dλ=∏1≤i<j≤dλi−λj+j−ij−i.d_\lambda=\prod_{1\le i<j\le d}\frac{\lambda_i-\lambda_j+j-i}{j-i}.dλ​=1≤i<j≤d∏​j−iλi​−λj​+j−i​.

This explicit index set and dimension formula come from equations (20), (22), and (23) of the source. The zero- and one-dimensional cases are included in the formal statement; their nontrivial index set can be empty.

Formalization targets

The goal is the corrected positive-threshold form of Theorem 1, for S≥1S\ge1S≥1 and 0<δ<10<\delta<10<δ<1:

Pr⁡(δ(νS,t)≥δ)≤2e−δSartanh⁡(δ)(1−δ2)S/2∑λ∈Λtdλ.\Pr\bigl(\delta(\nu_S,t)\ge\delta\bigr)\le \frac{2e^{-\delta S\operatorname{artanh}(\delta)}}{(1-\delta^2)^{S/2}} \sum_{\lambda\in\Lambda_t}d_\lambda.Pr(δ(νS​,t)≥δ)≤(1−δ2)S/22e−δSartanh(δ)​λ∈Λt​∑​dλ​.

The paper prints “any δ<1\delta<1δ<1.” Its formula fails for some nonpositive δ\deltaδ: a negative threshold makes the event certain while the displayed expression can decrease below one as SSS grows. At δ=0\delta=0δ=0, an empty Λt\Lambda_tΛt​ also gives a zero right-hand side for a certain event. The positive-threshold range is the meaningful form of its result.

The milestone list follows the paper's numbered claims. Fact 2 provides a master concentration bound for independent complex matrices through Hermitian dilation. Theorem 18 specializes it to one irreducible block, with its two equivalent closed forms of the tail factor. Lemma 16 and equation (24) connect the full design distance to the norms of those blocks and state the resulting union bound. Fact 9 supplies the decomposition indexed by Λt\Lambda_tΛt​ and the Weyl dimensions needed to turn the block sum into Theorem 1's explicit sum.

What the result provides

The bound gives a finite-sample guarantee for the mixed tensor moment of random gates. It exposes how an accuracy threshold and a representation-theoretic dimension sum determine the chance that the empirical moment differs from Haar averaging. A reader can evaluate the right-hand side once ddd, ttt, SSS, and δ\deltaδ are fixed. The bound also covers Haar random gates because Haar measure itself is an exact design at every order, as the paper observes in Section 6.

The mathematical result was proved by Dulian and Sawicki; the machine-checked development requested here remains to be built. Existing published Prove2Me modules already provide a spectral matrix norm, a Hermitian dilation, and a general matrix master bound. The new formalization must establish the paper's mixed tensor representation model, its irreducible decomposition and weight dimensions, the one-block estimate, and their assembly into the displayed inequality. These components can serve later results on random unitary designs and matrix concentration.

Main difficulty

The operator Ut,tU^{t,t}Ut,t acts on a space of dimension d2td^{2t}d2t, so applying a single matrix tail bound directly to it leaves a prefactor governed by that large ambient dimension. The paper's sharper expression depends on separating the nontrivial irreducible blocks, removing the Haar-invariant part, and identifying the dimensions of exactly the blocks that occur. The critical representation-theoretic step is the complete, multiplicity-aware decomposition in Fact 9. A bound for an arbitrary collection of block matrices would not identify the paper's Λt\Lambda_tΛt​ or its Weyl dimension sum.

Formalization scope

Lean represents U(d)U(d)U(d) as Matrix.unitaryGroup (Fin d) ℂ with the measurable space induced from the published Borel structure on complex matrices. The mixed tensor basis is indexed by a pair of functions from Fin t to Fin d; ordinary factors come first, conjugate factors second. The measure μ\muμ is required to be a left- and right-invariant probability measure. An exact design is a probability measure with equality of the full mixed tttth moment, not merely a first moment or a one-sided tensor power. Independent samples use the product measure, and the empirical moment is their average with multiplicity.

The norm is the published L2L^2L2 operator norm on matrices. The set Λt\Lambda_tΛt​ is a finite set of integer tuples; bounds −t≤λi≤t-t\le\lambda_i\le t−t≤λi​≤t follow from its defining constraints. The Weyl product uses zero-based Fin d indices, which preserve every difference j−ij-ij−i. All real exponents are real powers, with positive bases in the stated threshold range. The supremum over zero nontrivial blocks is defined to be zero, matching the zero design distance in that case.

The representation structure requires positive dimensions and multiplicities, irreducibility, pairwise inequivalence, orthogonal isometric embeddings, completeness, and intertwining with the concrete mixed tensor action. Those requirements prevent a vacuous or incomplete block family from making the goal automatic. Contributions are welcome on the representation decomposition, the Haar projection onto the trivial part, the non-Hermitian matrix bound, and the probability-to-block reduction. The source's highest-weight labels are kept: the block indexed by λ∈Λt\lambda\in\Lambda_tλ∈Λt​ has λ\lambdaλ as its highest weight, expressed through weights of the diagonal torus and the dominance order of the simple roots Li−Li+1L_i-L_{i+1}Li​−Li+1​, and its dimension is the Weyl product dλd_\lambdadλ​.

Selected references

  • C. Dulian and A. Sawicki, Matrix concentration inequalities and efficiency of random universal sets of quantum gates, arXiv preprint (2023), arXiv:2202.05371v3.
  • J. A. Tropp, An Introduction to Matrix Concentration Inequalities, Foundations and Trends in Machine Learning, 2015, doi:10.1561/2200000048.
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AlgebraCategory TheoryLinear algebra·Captain: mikedeng1

Higher-Dimensional Algebra VI: Lie 2-Algebras: The Category of Semistrict Lie 2-Algebras Is Equivalent to the Category of 2-Term L∞-AlgebrasResearch Paper

Motivation

An ordinary Lie algebra has a vector space and an antisymmetric bracket satisfying the Jacobi identity. In a Lie 2-algebra, the vectors become the objects of a linear category, and the Jacobi identity is witnessed by a morphism called the Jacobiator. This lets the Jacobi identity hold coherently rather than as a strict equation. Baez and Crans developed this notion to make the relation between categorified Lie algebra structures and short chain complexes precise (Baez–Crans, §§3–4). The result of interest here is their equivalence between semistrict Lie 2-algebras and two-term L∞L_\inftyL∞​-algebras, Theorem 36.

Setting

A 2-vector space is a category internal to vector spaces over a field kkk: its objects V0V_0V0​ and morphisms V1V_1V1​ are vector spaces; source sss, target ttt, identity iii, and composition are linear. Composition is read in diagrammatic order, so fgfgfg means first fff, then ggg. The identity laws require s(i(x))=t(i(x))=xs(i(x))=t(i(x))=xs(i(x))=t(i(x))=x. Lemma 6 shows that linearity forces the composition of composable fff and ggg to be

fg=f+g−i(t(f)).fg=f+g-i(t(f)).fg=f+g−i(t(f)).

The arrow part of fff is f⃗=f−i(s(f))∈ker⁡s\vec f=f-i(s(f))\in\ker sf​=f−i(s(f))∈kers. It remembers the displacement of fff after its source is translated to zero. A 2-vector space can therefore be compared with the two-term complex ker⁡s→tV0\ker s\xrightarrow{t}V_0kerst​V0​. Conversely, a complex C1→dC0C_1\xrightarrow{d}C_0C1​d​C0​ gives arrows (x,h)∈C0⊕C1(x,h)\in C_0\oplus C_1(x,h)∈C0​⊕C1​ with source xxx, target x+dhx+d hx+dh, and identity (x,0)(x,0)(x,0) (Baez–Crans, Proposition 8).

A semistrict Lie 2-algebra is a 2-vector space with a skew-symmetric bilinear bracket functor and a completely antisymmetric trilinear natural isomorphism

Jx,y,z:[[x,y],z]⟶[x,[y,z]]+[[x,z],y].J_{x,y,z}: [[x,y],z]\longrightarrow[x,[y,z]]+[[x,z],y].Jx,y,z​:[[x,y],z]⟶[x,[y,z]]+[[x,z],y].

The Jacobiator obeys the Jacobiator identity, an equality between two composites of morphisms through the octagon in Definition 22. A homomorphism FFF is a linear functor equipped with a bilinear natural transformation F2(x,y):[F0x,F0y]→F0[x,y]F_2(x,y):[F_0x,F_0y]\to F_0[x,y]F2​(x,y):[F0​x,F0​y]→F0​[x,y] satisfying Definition 23’s square. The resulting one-cell category is Lie2Alg\mathrm{Lie2Alg}Lie2Alg (Baez–Crans, pp. 18–21).

A 2-term L∞L_\inftyL∞​-algebra has vector spaces V1,V0V_1,V_0V1​,V0​, a differential d:V1→V0d:V_1\to V_0d:V1​→V0​, brackets l2l_2l2​ of degrees adding to at most one, and a trilinear map l3:V03→V1l_3:V_0^3\to V_1l3​:V03​→V1​. Its equations are precisely (a)–(i) of Lemma 33. In particular, d(l3)d(l_3)d(l3​) measures the failure of the ordinary Jacobi identity, and equation (i) is its four-input coherence law. Homomorphisms φ=(φ0,φ1,φ2)\varphi=(\varphi_0,\varphi_1,\varphi_2)φ=(φ0​,φ1​,φ2​) are chain maps with a skew bilinear comparison map satisfying all three equations of Definition 34. They form 2TermL∞\mathrm{2Term}L_\infty2TermL∞​ (Baez–Crans, pp. 28–30).

Formalization targets

The goal is Theorem 36, an equivalence of the two one-cell categories:

Lie2Alg≃2TermL∞.\mathrm{Lie2Alg}\simeq\mathrm{2Term}L_\infty.Lie2Alg≃2TermL∞​.

The milestone path begins with Lemma 6’s forced composition law. Proposition 8 states the underlying linear equivalence 2Vect≃2Term\mathrm{2Vect}\simeq\mathrm{2Term}2Vect≃2Term, and the 2-cell part of Theorem 12 identifies linear natural transformations between linear functors with chain homotopies between the corresponding chain maps, through their arrow parts. Propositions 25 and 35 establish identity, composition, and associativity for the homomorphisms on each side. Equation (3) reconciles the two expressions for the bracket of morphisms under the construction TTT. The proof of Theorem 36 then supplies TTT on objects and morphisms and the reverse construction SSS. The goal additionally requires functoriality and natural isomorphisms, which the paper asks the reader to check or construct (Baez–Crans, pp. 30–36).

Significance

The equivalence says that the categorical and chain-complex descriptions carry the same one-cell algebraic information. It permits constructions expressed with morphisms, functors, and a Jacobiator to be studied with a differential and higher brackets, and conversely. Later classifications of skeletal Lie 2-algebras in the paper use the two-term viewpoint (Baez–Crans, §§5–6).

Theorem 36 is proved in the cited paper; the machine-checked proof is the work this mission seeks. The local files compile the definitions and open theorem statements, and a sorry-free check exhibits nonzero carriers satisfying the principal structures. The milestones expose the individual obligations that a complete Lean proof must discharge. This mission does not claim a formal proof of the result or of the stronger 2-categorical statement.

Difficulty

A bilinear bracket on objects and morphisms is not enough to define a bracket functor: it must preserve source, target, identity, and simultaneous composition. In the TTT direction, two ways of decomposing a pair of morphisms suggest different bracket formulas. Their equality is equation (3), using Lemma 33(f). In the SSS direction, the interaction of two degree-one elements comes from the bracket functor’s preservation of a commuting square. The Jacobiator’s naturality and octagon must then correspond to the remaining L∞L_\inftyL∞​ identities. Finally, the constructions must act on homomorphisms and yield natural isomorphisms of functors (Baez–Crans, pp. 31–36).

Formalization scope

The field kkk has characteristic different from two in Theorem 36 and its §4.3 milestones, matching the standing assumption on p. 27. The §3 and §4.1 results retain the paper’s broader field convention. All vector spaces are unrestricted in dimension. A 2-vector space stores V0,V1,s,t,iV_0,V_1,s,t,iV0​,V1​,s,t,i and defines its composition by Lemma 6. A 2-term L∞L_\inftyL∞​-algebra is represented directly by Lemma 33(a)–(i), with [h,x]=−[x,h][h,x]=-[x,h][h,x]=−[x,h] and [h,k]=0[h,k]=0[h,k]=0; the general graded Definition 32 is outside scope.

The two categories are represented by raw object and morphism data with explicit predicates for lawful homomorphisms. An equivalence consists of functors preserving lawful morphisms, identities, and composites, together with natural isomorphisms in both directions. This representation keeps Propositions 25 and 35 as proof obligations and expresses the one-categorical content of Theorem 36. The stronger Theorem 39 asserts a 2-equivalence, but its 2-cell work is left without proof in the source and is not the goal here.

The Lie 2-algebra side retains the bracket’s functoriality on composable morphisms, the full naturality square, and the Jacobiator octagon. Its coherence is not replaced by Lemma 33’s equations: doing so would collapse the goal into a comparison of two copies of the same definition. The infrastructure for two-term complexes, 2-vector spaces, raw categories, curried multilinear maps, and their homomorphisms is reusable. Of Theorem 12 only the 2-cell correspondence is stated; the 2-functoriality of S,TS,TS,T and the 2-naturality of the comparison isomorphisms are not. Of Proposition 25 only the one-cell category laws are stated; the 2-homomorphisms of Definition 24 are not. A formalization in which the Lie 2-algebra side is defined by arrow-part equations, or in which the equivalence omits the natural isomorphisms or the category laws, would trivialize the goal and is excluded. Contributions proving the displayed category laws, the SSS and TTT constructions, their functoriality, and the two natural isomorphisms are welcome.

Selected references

  • John C. Baez and Alissa S. Crans, Higher-Dimensional Algebra VI: Lie 2-Algebras, arXiv:math/0307263v6, 2010 preprint. arXiv
  • John C. Baez and Alissa S. Crans, Higher-Dimensional Algebra VI: Lie 2-Algebras, Theory and Applications of Categories 12 (2004), 492–538 (journal version; theorem numbers in this mission follow the arXiv v6). TAC
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Functional AnalysisQuantum InformationRepresentation Theory·Captain: mikedeng1

Characterization of equivariant maps and application to entanglement detection: Unitarily Equivariant t-Positive Maps Detect Every State a Given t-Positive Map DetectsResearch Paper

Motivation

Positive maps give tests for entanglement in bipartite quantum states. A density matrix can pass one positive-map test and fail another, so the choice of map changes which states can be detected. Maps that behave predictably under unitary changes of basis are particularly structured, but that symmetry can appear restrictive. Bardet, Collins, and Sapra ask whether requiring unitary equivariance loses the ability to detect states that a given positive map detects. Their Theorem 5.1 says that it does not, provided one permits a sequence of larger output matrix algebras. Bardet, Collins, and Sapra, §5

The question sits between two familiar perspectives. The positive-map criterion tests a state by applying a map to one subsystem; unitary equivariance controls how that map reacts when the subsystem is rotated. The paper's result shows that a specified detector can be recovered, in the limit of a nested family, within this symmetric class. It addresses a fixed input map and a fixed ancillary dimension. The paper separately states a more uniform corollary about Schmidt number, but that corollary is outside this mission. Bardet, Collins, and Sapra, Theorem 5.1 and Corollary 5.4

Setting

Write Mn(C)M_n(\mathbb C)Mn​(C) for complex n×nn\times nn×n matrices and UnU_nUn​ for their unitary group. A complex linear map ϕ:Mn(C)→MN(C)\phi:M_n(\mathbb C)\to M_N(\mathbb C)ϕ:Mn​(C)→MN​(C) is ttt-positive if idt⊗ϕ\mathrm{id}_t\otimes\phiidt​⊗ϕ sends every positive semidefinite matrix on Ct⊗Cn\mathbb C^t\otimes\mathbb C^nCt⊗Cn to a positive semidefinite matrix. It is completely positive if it is rrr-positive for every natural number rrr. A map Φ:Mn(C)→MD(C)\Phi:M_n(\mathbb C)\to M_D(\mathbb C)Φ:Mn​(C)→MD​(C) is unitarily equivariant if, for each U∈UnU\in U_nU∈Un​, there is one unitary V∈UDV\in U_DV∈UD​ satisfying Φ(UXU∗)=VΦ(X)V∗\Phi(UXU^*)=V\Phi(X)V^*Φ(UXU∗)=VΦ(X)V∗ for every X∈Mn(C)X\in M_n(\mathbb C)X∈Mn​(C). The choice of VVV may depend on UUU and Φ\PhiΦ, while the equality must hold for all XXX. Bardet, Collins, and Sapra, Definition 2.1

A density matrix on Cm⊗Cn\mathbb C^m\otimes\mathbb C^nCm⊗Cn is positive semidefinite and has trace one. The detection set of ϕ\phiϕ at ancillary dimension mmm is

Sm(ϕ)={ρ:ρ≥0, Tr⁡ρ=1, (idm⊗ϕ)(ρ)≥0}.S_m(\phi)=\{\rho:\rho\geq0,\ \operatorname{Tr}\rho=1,\ (\mathrm{id}_m\otimes\phi)(\rho)\geq0\}.Sm​(ϕ)={ρ:ρ≥0, Trρ=1, (idm​⊗ϕ)(ρ)≥0}.

Here ϕ\phiϕ acts on the second tensor factor. A state outside Sm(ϕ)S_m(\phi)Sm​(ϕ) is detected by ϕ\phiϕ: applying idm⊗ϕ\mathrm{id}_m\otimes\phiidm​⊗ϕ produces an operator that is not positive semidefinite. No trace preservation or unitality is required of ϕ\phiϕ. Bardet, Collins, and Sapra, equation (17)

Formalization targets

Main theorem

Fix m,n,N,tm,n,N,tm,n,N,t with 1≤t≤min⁡{m,n}1\leq t\leq\min\{m,n\}1≤t≤min{m,n} and a ttt-positive map ϕ:Mn(C)→MN(C)\phi:M_n(\mathbb C)\to M_N(\mathbb C)ϕ:Mn​(C)→MN​(C) that is not completely positive. The target is one family Φa:Mn(C)→MNa(C)\Phi_a:M_n(\mathbb C)\to M_{N_a}(\mathbb C)Φa​:Mn​(C)→MNa​​(C), chosen before any state ρ\rhoρ, for which each member is unitarily equivariant and ttt-positive, Na→∞N_a\to\inftyNa​→∞, and

Sm(Φa+1)⊆Sm(Φa),⋂a≥1Sm(Φa)⊆Sm(ϕ).S_m(\Phi_{a+1})\subseteq S_m(\Phi_a),\qquad \bigcap_{a\geq1}S_m(\Phi_a)\subseteq S_m(\phi).Sm​(Φa+1​)⊆Sm​(Φa​),a≥1⋂​Sm​(Φa​)⊆Sm​(ϕ).

Thus the family eventually detects every state detected by ϕ\phiϕ, and detection persists at later indices. The ancillary dimension mmm is fixed before the family is chosen. Bardet, Collins, and Sapra, Theorem 5.1

Intermediate targets

The milestone statements cover the infinite dimensional lift of a linear map to H=L2(Un,CN)H=L^2(U_n,\mathbb C^N)H=L2(Un​,CN), its inclusion Sm(Φ)⊆Sm(ϕ)S_m(\Phi)\subseteq S_m(\phi)Sm​(Φ)⊆Sm​(ϕ), the finite dimensional invariant subspaces supplied by the Peter–Weyl decomposition, and the compression of the lift to such a subspace, which is a unitarily equivariant ttt-positive matrix map Ψ\PsiΨ with Sm(Φ)⊆Sm(Ψ)S_m(\Phi)\subseteq S_m(\Psi)Sm​(Φ)⊆Sm​(Ψ). These are the source's Lemma 5.3, Theorem 5.2 for its explicit witness, the consequence of equations (24)–(25) used in §5.2, and the compression step of the proof of Theorem 5.1 on pp. 14–15. The milestone for Theorem 5.2 names the particular fibrewise lift constructed in the paper as its witness and asserts its equivariance, its ttt-positivity and the inclusion of detection sets. Bardet, Collins, and Sapra, §5.1–5.2

Significance

The theorem shows that symmetry alone does not prevent a positive map from detecting the states detected by a specified input map. It turns a single detector into a nested family with growing finite output dimensions, while keeping the same positivity order. The conclusion is pointwise in states but uses one sequence uniformly across all density matrices at the fixed ancillary dimension: each state outside Sm(ϕ)S_m(\phi)Sm​(ϕ) is excluded from every sufficiently late Sm(Φa)S_m(\Phi_a)Sm​(Φa​). The result does not assert that any one finite output dimension suffices for every state. Bardet, Collins, and Sapra, Theorem 5.1

The paper proves this mathematical result. This mission records its statements in Lean, leaving proofs of the drafted goal and milestones to formalization work. The finite matrix definitions and the infinite dimensional L2L^2L2 interface can be reused for other questions about positive maps, regular representations, and finite dimensional compression. The published tensor superoperator and complete positivity definitions are shared with other quantum information developments rather than redefined here.

Difficulty

The immediate detector ϕ\phiϕ need not be unitarily equivariant. Replacing it by a single symmetric finite matrix map therefore gives no direct reason to preserve all of its detected states. The source passes through a fibrewise map indexed by every input unitary, so the intermediate output space is infinite dimensional. The remaining difficulty is to return to finite matrix outputs while retaining both equivariance and ttt-positivity, and to choose the outputs so their detection sets are nested. A finite dimensional truncation without invariance under the regular action would not establish the claimed symmetry. Bardet, Collins, and Sapra, §5.1–5.2

Formalization scope

Finite matrices are Matrix (Fin n) (Fin n) ℂ; positive semidefiniteness is Matrix.PosSemidef. The ancillary factor is first in Fin m × Fin n, and the existing QAlgorithms.idTensorSuperop applies the map to the second factor. Complete positivity is the published QAlgorithms.Entanglement.IsCompletelyPositive. The paper's indices a≥1a\geq1a≥1 become Lean natural numbers starting at zero. The density matrix test includes both positivity and trace one. The output dimensions form an actual function tending to infinity, and the maps form a dependent family whose codomain uses that function. The goal keeps the printed “not completely positive” hypothesis and all five stated conclusions. In particular, choosing detectors separately for each state would not meet it.

For the intermediate result, HHH is a complex L2L^2L2 space over a Borel measure on UnU_nUn​. The lift is encoded by its sesquilinear form, whose kernel at UUU is ϕ(U∗XU)\phi(U^*XU)ϕ(U∗XU); positivity on Ct⊗H\mathbb C^t\otimes HCt⊗H is tested by all block quadratic forms. A finite measure and two L2L^2L2 vectors make these integrals integrable because the matrix kernel is bounded. The regular action uses left invariance; the detection inclusion uses positivity of nonempty open sets; the Peter–Weyl milestone uses Haar probability measure. These are properties of the paper's Haar measure. The source's standing convention that linear maps preserve adjoints is already implied by ttt-positivity for the goal and is not a separate assumption there. The general linear map in the lift milestones is stated exactly where the source permits it.

The development needs the shared matrix-map definitions, the L2L^2L2 and measure interfaces, and finite dimensional unitary representation theory. Work on the bounded-operator interpretation of the form, invariant truncations, and compression can be reused beyond this mission. The paper's inconsistent phrase “Schmidt number smaller than ttt” is not encoded, because the target uses only detection sets. Bardet, Collins, and Sapra, pp. 12–15

Selected references

  • I. Bardet, B. Collins, and G. Sapra, Characterization of equivariant maps and application to entanglement detection, arXiv preprint, 2019, arXiv:1811.08193v3.
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Differential GeometryLinear algebraMathematical Physics·Captain: mikedeng1

Geometrization of Quantum Mechanics: The Unitary Momentum Map Pulls Back the Lie and Jordan Tensors of the Observables to the Kähler Structure of Hilbert SpaceResearch Paper

Motivation

Quantum mechanics is usually written in linear-algebraic terms: states are vectors of a complex Hilbert space, observables are Hermitian operators, and expectation values pair the two. Classical mechanics is written geometrically: states form a symplectic manifold, observables are functions on it, and dynamics is a Hamiltonian flow. A line of work starting with Kibble (1979) and continued by Cirelli, Lanzavecchia, Heslot, Ashtekar–Schilling (arXiv:gr-qc/9706069) and Brody–Hughston (arXiv:quant-ph/9906086) recasts quantum mechanics in the classical language: the Hilbert space, seen as a real manifold, carries a Kähler structure (a symplectic form, a Euclidean metric and a compatible complex structure), and observables become real quadratic functions on it.

Cariñena, Clemente-Gallardo and Marmo (arXiv:math-ph/0701053v2) organise this correspondence around one map, the momentum map of the unitary group acting on Hilbert space. The algebra of observables carries two products, a Lie product (the commutator) and a Jordan product (the anticommutator). The paper's Proposition 5 states that the momentum map carries both products, read as tensors on the dual of the unitary Lie algebra, to the symplectic and Euclidean parts of the Kähler structure of Hilbert space. This mission formalizes that statement in finite dimension.

Setting

Fix n∈Nn\in\mathbb Nn∈N and let H=Cn\mathcal H=\mathbb C^nH=Cn, with ⟨ψ∣ϕ⟩=∑kψk‾ϕk\langle\psi|\phi\rangle=\sum_k\overline{\psi_k}\phi_k⟨ψ∣ϕ⟩=∑k​ψk​​ϕk​. The space of observables O\mathcal OO is the real vector space of Hermitian n×nn\times nn×n complex matrices. On it the paper defines:

  • the isomorphism α(A)=iA\alpha(A)=iAα(A)=iA onto the Lie algebra u(n)\mathfrak u(n)u(n) of anti-Hermitian matrices, eq. (2);
  • the Lie product [A,B]−=α−1(α(A)α(B)−α(B)α(A))=i(AB−BA)[A,B]_-=\alpha^{-1}(\alpha(A)\alpha(B)-\alpha(B)\alpha(A))=i(AB-BA)[A,B]−​=α−1(α(A)α(B)−α(B)α(A))=i(AB−BA), eq. (3);
  • the scalar product ⟨A,B⟩=12Tr⁡(AB)\langle A,B\rangle=\tfrac12\operatorname{Tr}(AB)⟨A,B⟩=21​Tr(AB), eq. (4);
  • the Jordan product A∘B=12(AB+BA)A\circ B=\tfrac12(AB+BA)A∘B=21​(AB+BA), eq. (6).

Through (4), the dual u∗(n)\mathfrak u^*(n)u∗(n) is identified with Hermitian matrices ξ\xiξ. Each observable AAA gives a linear function A^(ξ)=12Tr⁡(ξA)\widehat A(\xi)=\tfrac12\operatorname{Tr}(\xi A)A(ξ)=21​Tr(ξA). On u∗(n)\mathfrak u^*(n)u∗(n) the paper defines the Lie–Poisson tensor (11), Λ(dA^,dB^)(ξ)=i2Tr⁡ ξ(α(A)α(B)−α(B)α(A))\Lambda(d\widehat A,d\widehat B)(\xi)=\tfrac i2\operatorname{Tr}\,\xi(\alpha(A)\alpha(B)-\alpha(B)\alpha(A))Λ(dA,dB)(ξ)=2i​Trξ(α(A)α(B)−α(B)α(A)), and the Jordan tensor (12), R(ξ)(dA^,dB^)=12Tr⁡ ξ(AB+BA)\mathcal R(\xi)(d\widehat A,d\widehat B)=\tfrac12\operatorname{Tr}\,\xi(AB+BA)R(ξ)(dA,dB)=21​Trξ(AB+BA).

On the Hilbert space side, use real coordinates zk=qk+ipkz_k=q_k+ip_kzk​=qk​+ipk​. Every complex matrix AAA defines the quadratic function fA(ψ)=12⟨ψ∣Aψ⟩f_A(\psi)=\tfrac12\langle\psi|A\psi\ranglefA​(ψ)=21​⟨ψ∣Aψ⟩. The canonical Poisson bracket is {f,g}=∑k(∂qkf ∂pkg−∂pkf ∂qkg)\{f,g\}=\sum_k(\partial_{q_k}f\,\partial_{p_k}g-\partial_{p_k}f\,\partial_{q_k}g){f,g}=∑k​(∂qk​​f∂pk​​g−∂pk​​f∂qk​​g), and the contravariant Euclidean structure is G=∑k(∂qk⊗∂qk+∂pk⊗∂pk)G=\sum_k(\partial_{q_k}\otimes\partial_{q_k}+\partial_{p_k}\otimes\partial_{p_k})G=∑k​(∂qk​​⊗∂qk​​+∂pk​​⊗∂pk​​). The momentum map is

μ:Cn→u∗(n),μ(ψ)=ρψ=∣ψ⟩⟨ψ∣.\mu:\mathbb C^n\to\mathfrak u^*(n),\qquad \mu(\psi)=\rho_\psi=|\psi\rangle\langle\psi| .μ:Cn→u∗(n),μ(ψ)=ρψ​=∣ψ⟩⟨ψ∣.

Formalization targets

Goal: Proposition 5 (p. 12)

For Hermitian A,BA,BA,B and every ψ∈Cn\psi\in\mathbb C^nψ∈Cn:

A^(μ(ψ))=fA(ψ),{fA,fB}(ψ)=Λ(dA^,dB^)(μ(ψ)),G(dfA,dfB)(ψ)=R(μ(ψ))(dA^,dB^).\widehat A(\mu(\psi))=f_A(\psi),\qquad \{f_A,f_B\}(\psi)=\Lambda(d\widehat A,d\widehat B)(\mu(\psi)),\qquad G(df_A,df_B)(\psi)=\mathcal R(\mu(\psi))(d\widehat A,d\widehat B).A(μ(ψ))=fA​(ψ),{fA​,fB​}(ψ)=Λ(dA,dB)(μ(ψ)),G(dfA​,dfB​)(ψ)=R(μ(ψ))(dA,dB).

In the paper's notation: μ∗(A^)=fA\mu^*(\widehat A)=f_Aμ∗(A)=fA​, μ∗({A^,B^})={fA,fB}\mu^*(\{\widehat A,\widehat B\})=\{f_A,f_B\}μ∗({A,B})={fA​,fB​} and μ∗(R(dA^,dB^))=G(μ∗(dA^),μ∗(dB^))\mu^*(\mathcal R(d\widehat A,d\widehat B))=G(\mu^*(d\widehat A),\mu^*(d\widehat B))μ∗(R(dA,dB))=G(μ∗(dA),μ∗(dB)).

Milestones

In attack order:

  1. Lemma 5 (p. 12): fAf_AfA​ is real-valued for all ψ\psiψ if and only if AAA is Hermitian.
  2. Lemma 1 (p. 4), in two parts:
    • [⋅,⋅]−[\cdot,\cdot]_-[⋅,⋅]−​ makes O\mathcal OO a real Lie algebra, isomorphic to u(n)\mathfrak u(n)u(n) through α\alphaα;
    • 12Tr⁡(AB)\tfrac12\operatorname{Tr}(AB)21​Tr(AB) is a real, symmetric, positive definite scalar product, invariant under A↦UAU†A\mapsto UAU^\daggerA↦UAU†.
  3. Lemma 2 (p. 5): (O,∘)(\mathcal O,\circ)(O,∘) is a Jordan algebra.
  4. Proposition 1 (p. 5): the scalar product is invariant for both products (7), and ad−\mathrm{ad}_-ad−​ is a derivation of ∘\circ∘ (8).
  5. Lemma 3 (p. 5): O\mathcal OO is a Jordan–Lie algebra. This means the Lie and Jordan algebra axioms hold, (8) holds together with the associator identity (9), (A∘B)∘C−A∘(B∘C)=14ℏ[[A,C]−,B]−(A\circ B)\circ C-A\circ(B\circ C)=\tfrac14\hbar[[A,C]_-,B]_-(A∘B)∘C−A∘(B∘C)=41​ℏ[[A,C]−​,B]−​, here with ℏ=1\hbar=1ℏ=1.
  6. Equivariance (§3.1.1, p. 11): μ\muμ takes values in u∗(n)\mathfrak u^*(n)u∗(n) and μ(Uψ)=Uμ(ψ)U†\mu(U\psi)=U\mu(\psi)U^\daggerμ(Uψ)=Uμ(ψ)U† for unitary UUU.

Significance

Proposition 5 says that the algebra of observables can be read off Hilbert space geometrically:

  • commutators of observables become Poisson brackets of their expectation-value functions;
  • anticommutators become the metric pairing of their gradients.

This is the dictionary behind geometric treatments of the Schrödinger equation as a Hamiltonian flow. It also underlies variance and uncertainty relations written through the metric, and the reduction to projective space and density states that the paper discusses in §§2.5 and 4. The paper presents it as an alternative to the GNS construction for pure states.

The paper's proof is "Direct verification", and Lemmas 1–3 and Proposition 1 are classical facts about Hermitian matrices. No step is open. What the mission adds is a machine-checked version with every normalisation pinned, as listed in Formalization scope:

  • the factors ½ in (4), (6) and fAf_AfA​;
  • the factor i/2i/2i/2 in (11);
  • ℏ=1\hbar=1ℏ=1 in (9).

The paper uses both the Hermitian picture (3), (4), (6) and the anti-Hermitian picture (5), (11). The formal statement fixes the signs and factors needed to read their relation precisely. The prior-art search for this mission found no published Prove2Me statement with the same finite-dimensional objects and conclusion.

Difficulty

The algebraic milestones are short computations once the definitions are unfolded. The work concentrates in the goal, whose two sides live in different worlds.

The left side is built from real partial derivatives of real-valued functions on Cn\mathbb C^nCn, viewed as R2n\mathbb R^{2n}R2n. Its derivatives must be computed in the directions eke_kek​ and iekie_kiek​ and then recombined into complex inner products.

The right side is a trace of a product of matrices with the rank-one matrix ∣ψ⟩⟨ψ∣|\psi\rangle\langle\psi|∣ψ⟩⟨ψ∣.

The difficulty is that the derivative formulas use real coordinates while the tensor formulas use complex matrix products and traces. Their normalizations and sign conventions must agree at the level of the full identity, including the iii in α(A)\alpha(A)α(A) and the factors of 12\tfrac1221​ in the quadratic functions.

Replacing the derivative-defined brackets by their closed forms would make the goal trivial and is not permitted, see below.

Formalization scope

All objects are defined in one definitions module in the namespace GeomQM.MomentumMap, over Mathlib's Matrix (Fin n) (Fin n) ℂ and vectors Fin n → ℂ.

Committed conventions.

  • Observables carry an explicit IsHermitian hypothesis. Lemma 5 is about an arbitrary complex matrix, and equivariance needs no hypothesis. n=0n=0n=0 is allowed, since every statement then holds trivially, as in the paper.
  • ∂/∂qk\partial/\partial q_k∂/∂qk​ and ∂/∂pk\partial/\partial p_k∂/∂pk​ are fderiv ℝ applied to Pi.single k 1 and Pi.single k I. This is the paper's zk=qk+ipkz_k=q_k+ip_kzk​=qk​+ipk​.
  • fAf_AfA​ is defined as the complex number 12⟨ψ∣Aψ⟩\tfrac12\langle\psi|A\psi\rangle21​⟨ψ∣Aψ⟩, and the real function used in the goal is its real part. Lemma 5 is stated on the complex value, so that it is not vacuous.
  • u∗(n)\mathfrak u^*(n)u∗(n) is the space of Hermitian matrices. A^\widehat AA uses the pairing (4), 12Tr⁡(ξA)\tfrac12\operatorname{Tr}(\xi A)21​Tr(ξA), not the pairing (5), which differs by a factor iii on α(A)\alpha(A)α(A) and would change the sign.
  • Λ\LambdaΛ is (11) applied literally to α(A),α(B)\alpha(A),\alpha(B)α(A),α(B). The shortcut [A,B]−^\widehat{[A,B]_-}[A,B]−​​ has the opposite sign.
  • R\mathcal RR is the right-most expression of (12).
  • The real-valued tensors take the real part of trace expressions that are real for Hermitian arguments.
  • The second bracket {f1,f2}+\{f_1,f_2\}_+{f1​,f2​}+​ displayed on p. 12 is not used, because Proposition 5 names GGG.

Ruled out. The brackets on Cn\mathbb C^nCn are defined through real derivatives of arbitrary functions, never as f−i[A,B]f_{-i[A,B]}f−i[A,B]​ or fAB+BAf_{AB+BA}fAB+BA​. The tensors on u∗(n)\mathfrak u^*(n)u∗(n) are trace formulas, never rewritten as quadratic functions of ψ\psiψ. Either shortcut would make bullets 2 and 3 hold by definition.

Not in scope. The following are not formalized:

  • Propositions 2–4: the Poisson structure on all of O∗\mathcal O^*O∗, Lie derivatives of R\mathcal RR, and generalized distributions;
  • Lemma 4: linear dynamics preserving both products;
  • the Rayleigh-quotient statements of §3.4;
  • the projective-space material of §4.

Welcome contributions. Proofs of the milestones and of the goal, and general lemmas that would be reusable beyond this mission:

  • derivative formulas for real quadratic forms on Fin n → ℂ;
  • the identity Tr⁡(∣ψ⟩⟨ψ∣M)=⟨ψ∣Mψ⟩\operatorname{Tr}(|\psi\rangle\langle\psi|M)=\langle\psi|M\psi\rangleTr(∣ψ⟩⟨ψ∣M)=⟨ψ∣Mψ⟩.

Selected references

  • J. F. Cariñena, J. Clemente-Gallardo, G. Marmo, Geometrization of Quantum Mechanics, arXiv preprint, 2007 (v2). https://arxiv.org/abs/math-ph/0701053v2
  • T. W. B. Kibble, Geometrization of quantum mechanics, Communications in Mathematical Physics 65, 189–201, 1979. https://doi.org/10.1007/BF01225149
  • A. Ashtekar, T. A. Schilling, Geometrical formulation of quantum mechanics, in On Einstein's Path, Springer, 1998. https://arxiv.org/abs/gr-qc/9706069
  • D. C. Brody, L. P. Hughston, Geometric quantum mechanics, Journal of Geometry and Physics 38, 19–53, 2001. https://arxiv.org/abs/quant-ph/9906086
  • J. Grabowski, M. Kuś, G. Marmo, Geometry of quantum systems: density states and entanglement, Journal of Physics A 38, 10217–10244, 2005. https://arxiv.org/abs/math-ph/0507045
  • N. P. Landsman, Mathematical Topics Between Classical and Quantum Mechanics, Springer Monographs in Mathematics, 1998. https://doi.org/10.1007/978-1-4612-1680-3
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AlgebraMathematical Physics·Captain: mikedeng1

Continuum Limit of gl(M|N) Spin Chains: For an Odd Sourceless Simple Root, gl(M|N) Bethe Ansatz Solutions with Identified Neighbour Roots Are Exactly Lifts of gl(M−1|N−1) Solutions of Equal EnergyResearch Paper

Motivation

Integrable spin chains with a Lie superalgebra symmetry gl(M∣N)\mathfrak{gl}(M|N)gl(M∣N) are lattice regularizations of two-dimensional field theories with target-space supersymmetry, such as the gl(M∣N)\mathfrak{gl}(M|N)gl(M∣N) Gross–Neveu models and sigma models on superspaces, which appear in the study of disordered systems, polymers and the AdS/CFT correspondence. Their spectra are described by the nested Bethe ansatz: each eigenvalue of the transfer matrix corresponds to a family of complex numbers, the Bethe roots, solving a system of algebraic equations, the Bethe ansatz equations (BAE). The nested algebraic Bethe ansatz for general closed gl(M∣N)\mathfrak{gl}(M|N)gl(M∣N) chains was carried out by Belliard and Ragoucy (arXiv:0804.2822).

C. Candu, Continuum Limit of gl(M|N) Spin Chains (arXiv:1012.0050), studies the antiferromagnetic chain (V⊗V∗)⊗L(V\otimes V^*)^{\otimes L}(V⊗V∗)⊗L of alternating fundamental and dual representations. Its §4 shows that a class of solutions of the gl(M∣N)\mathfrak{gl}(M|N)gl(M∣N) BAE is fully characterized by solutions of the gl(M−1∣N−1)\mathfrak{gl}(M-1|N-1)gl(M−1∣N−1) BAE, which embeds the gl(M−1∣N−1)\mathfrak{gl}(M-1|N-1)gl(M−1∣N−1) spectrum into the gl(M∣N)\mathfrak{gl}(M|N)gl(M∣N) spectrum. This is the algebraic counterpart of cohomological reduction (Candu–Creutzig–Mitev–Schomerus, arXiv:1001.1344), in which the gl(M−1∣N−1)\mathfrak{gl}(M-1|N-1)gl(M−1∣N−1) chain is the cohomology of an odd nilpotent element acting on the gl(M∣N)\mathfrak{gl}(M|N)gl(M∣N) chain. The paper uses this relation to compare all gl(n+N∣N)\mathfrak{gl}(n+N|N)gl(n+N∣N) chains with nnn fixed, and concludes that their continuum limits share the gl(n)\mathfrak{gl}(n)gl(n) Gross–Neveu-like particle content.

This mission formalizes that restriction and lift of Bethe ansatz equations.

Setting

Let d=M+Nd = M+Nd=M+N and r=d−1r = d-1r=d−1. A grading assigns to each position i∈{1,…,d}i\in\{1,\dots,d\}i∈{1,…,d} a parity ∣i∣∈{0,1}|i|\in\{0,1\}∣i∣∈{0,1} and a sign σi=(−1)∣i∣\sigma_i = (-1)^{|i|}σi​=(−1)∣i∣; MMM counts the even and NNN the odd positions. The loop weight is n=∑i=1dσi=M−Nn=\sum_{i=1}^d\sigma_i = M-Nn=∑i=1d​σi​=M−N. The simple roots are αk=ϵk−ϵk+1\alpha_k = \epsilon_k-\epsilon_{k+1}αk​=ϵk​−ϵk+1​, k=1,…,rk=1,\dots,rk=1,…,r; αk\alpha_kαk​ is odd when σkσk+1=−1\sigma_k\sigma_{k+1}=-1σk​σk+1​=−1.

For a chain of length LLL the source terms are

Λ1(u)=(u+σ1)L(u+n2)L,Λi(u)=uL(u+n2)L (2≤i≤r),Λd(u)=uL(u+n2−σd)L.\Lambda_1(u)=(u+\sigma_1)^L(u+\tfrac n2)^L,\qquad \Lambda_i(u)=u^L(u+\tfrac n2)^L\ (2\le i\le r),\qquad \Lambda_d(u)=u^L(u+\tfrac n2-\sigma_d)^L .Λ1​(u)=(u+σ1​)L(u+2n​)L,Λi​(u)=uL(u+2n​)L (2≤i≤r),Λd​(u)=uL(u+2n​−σd​)L.

For each type k=1,…,rk=1,\dots,rk=1,…,r let {uj(k)}j=1ν(k)\{u^{(k)}_j\}_{j=1}^{\nu^{(k)}}{uj(k)​}j=1ν(k)​ be a finite set of pairwise distinct complex numbers and Qk(u)=∏j(u−uj(k))Q_k(u)=\prod_j(u-u^{(k)}_j)Qk​(u)=∏j​(u−uj(k)​), with Q0=Qd=1Q_0=Q_d=1Q0​=Qd​=1. The BAE (2.9) state that for every kkk and every root u=uj(k)u=u^{(k)}_ju=uj(k)​,

Λk(u)Λk+1(u)=−σkσk+1 Qk−1(u) Qk(u+σk+1) Qk+1(u−σk+1)Qk−1(u+σk) Qk(u−σk) Qk+1(u).\frac{\Lambda_k(u)}{\Lambda_{k+1}(u)}=-\sigma_k\sigma_{k+1}\,\frac{Q_{k-1}(u)\,Q_k(u+\sigma_{k+1})\,Q_{k+1}(u-\sigma_{k+1})}{Q_{k-1}(u+\sigma_k)\,Q_k(u-\sigma_k)\,Q_{k+1}(u)} .Λk+1​(u)Λk​(u)​=−σk​σk+1​Qk−1​(u+σk​)Qk​(u−σk​)Qk+1​(u)Qk−1​(u)Qk​(u+σk+1​)Qk+1​(u−σk+1​)​.

With xj(k)=i uj(k)+i2∑l≤kσlx^{(k)}_j = i\,u^{(k)}_j+\tfrac i2\sum_{l\le k}\sigma_lxj(k)​=iuj(k)​+2i​∑l≤k​σl​ (2.11), the energy (2.18) of a solution is

E=−∑jσ1(xj(1))2+1/4−∑jσd(xj(r))2+1/4.E=-\sum_{j}\frac{\sigma_1}{(x^{(1)}_j)^2+1/4}-\sum_{j}\frac{\sigma_d}{(x^{(r)}_j)^2+1/4} .E=−j∑​(xj(1)​)2+1/4σ1​​−j∑​(xj(r)​)2+1/4σd​​.

The paper works throughout under n=M−N>0n = M-N>0n=M−N>0.

Fix kkk with A1 (αk\alpha_kαk​ odd) and A2 (αk\alpha_kαk​ has no source term, k≠1,rk\neq 1,rk=1,r). R1 identifies the roots of types k−1k-1k−1 and k+1k+1k+1. The reduced system deletes grading positions k,k+1k,k+1k,k+1 and root types k,k+1k,k+1k,k+1: it is the BAE of a gl(M−1∣N−1)\mathfrak{gl}(M-1|N-1)gl(M−1∣N−1) chain with simple roots {α1,…,αk−2,ϵk−1−ϵk+2,αk+2,…,αr}\{\alpha_1,\dots,\alpha_{k-2},\epsilon_{k-1}-\epsilon_{k+2},\alpha_{k+2},\dots,\alpha_r\}{α1​,…,αk−2​,ϵk−1​−ϵk+2​,αk+2​,…,αr​}.

Formalization targets

Goal: restriction and lift (§4.1–4.2)

Under A1, A2, R1 and non-degeneracy of the roots,

BAEgl(M∣N)({u(l)}l=1r)  ⟺  BAEgl(M−1∣N−1)({u(l)}l≠k,k+1) ∧ (2.9)k−1 at the roots of type k−1,\text{BAE}_{\mathfrak{gl}(M|N)}(\{u^{(l)}\}_{l=1}^r)\iff \text{BAE}_{\mathfrak{gl}(M-1|N-1)}(\{u^{(l)}\}_{l\neq k,k+1})\ \wedge\ (2.9)_{k-1}\text{ at the roots of type }k-1,BAEgl(M∣N)​({u(l)}l=1r​)⟺BAEgl(M−1∣N−1)​({u(l)}l=k,k+1​) ∧ (2.9)k−1​ at the roots of type k−1,

and Egl(M∣N)=Egl(M−1∣N−1)E_{\mathfrak{gl}(M|N)} = E_{\mathfrak{gl}(M-1|N-1)}Egl(M∣N)​=Egl(M−1∣N−1)​. The forward direction is the restriction R1–R2; the backward direction is the reduction of the lift to "a solution … to either eq. (4.2) or eq. (4.4)".

Milestones

  1. Under A1–A2 the equations of types k−1k-1k−1, kkk, k+1k+1k+1 take the printed forms (4.2), (4.3), (4.4) (p. 17).
  2. Under R1, (4.3) holds automatically (p. 18).
  3. R2: (4.2) and (4.4) at a common root give (4.6), in which the type-kkk roots no longer appear (p. 18).
  4. The restricted equations are exactly the gl(M−1∣N−1)\mathfrak{gl}(M-1|N-1)gl(M−1∣N−1) BAE for the reduced simple root system, with the same loop weight nnn (p. 18).
  5. Given a reduced solution and R1, (4.2) and (4.4) are equivalent (p. 19).

Significance

The restriction gives an explicit map from gl(M−1∣N−1)\mathfrak{gl}(M-1|N-1)gl(M−1∣N−1) Bethe solutions to gl(M∣N)\mathfrak{gl}(M|N)gl(M∣N) Bethe solutions that preserves the energy. Iterated, it relates every gl(n+N∣N)\mathfrak{gl}(n+N|N)gl(n+N∣N) chain to the gl(n)\mathfrak{gl}(n)gl(n) chain, which is how the paper identifies the vacuum and the massive excitations of the gl(n+N∣N)\mathfrak{gl}(n+N|N)gl(n+N∣N) chains in the continuum limit (§5–§6). It is also a concrete, equation-level check of cohomological reduction.

The result is proved in the paper by direct algebra. The result is not formalized anywhere on Prove2Me, which has no Bethe ansatz equations of any kind. This mission produces a precise statement of the nested BAE with their grading-dependent signs, shifts and boundary conventions, and a verified version of the restriction, including the bookkeeping that the paper leaves implicit: the reindexing of types, the change of the source terms of the reduced chain, and the invariance of the energy.

Difficulty

Each step is elementary algebra; the difficulty is bookkeeping. The sign −σkσk+1-\sigma_k\sigma_{k+1}−σk​σk+1​, the shifts ±σk\pm\sigma_k±σk​, ±σk+1\pm\sigma_{k+1}±σk+1​ and the boundary cases Q0=Qd=1Q_0=Q_d=1Q0​=Qd​=1 differ between the original and the reduced system: after deletion, the neighbour of type k+2k+2k+2 is type k−1k-1k−1, and the last source term Λd\Lambda_dΛd​ and the partial sums ∑l≤kσl\sum_{l\le k}\sigma_l∑l≤k​σl​ in (2.11) are those of a different grading. A naive argument that matches equations by position, or that treats the reduced system with the original source terms, misses these shifts. The backward direction needs non-degeneracy, because recovering (4.4) from (4.6) and (4.2) requires dividing by the two sides of (4.2).

Formalization scope

Everything is in the namespace SuperBAE.Restriction and works over C\mathbb{C}C. Positions 1,…,d1,\dots,d1,…,d and types 1,…,d−11,\dots,d-11,…,d−1 are natural numbers, and a grading is a Boolean function (true = odd), with σi∈{±1}\sigma_i\in\{\pm1\}σi​∈{±1}. Root sets are Finset ℂ, which encodes the paper's requirement that no two roots of the same type coincide. QkQ_kQk​ equals 111 outside 1≤k≤d−11\le k\le d-11≤k≤d−1. Only the homogeneous chain is modelled. The BAE are in division form, so every theorem carries a regularity hypothesis: at each root uuu of type kkk, the values Λk(u)\Lambda_k(u)Λk​(u), Λk+1(u)\Lambda_{k+1}(u)Λk+1​(u), Qk−1(u+σk)Q_{k-1}(u+\sigma_k)Qk−1​(u+σk​), Qk(u−σk)Q_k(u-\sigma_k)Qk​(u−σk​) and Qk+1(u)Q_{k+1}(u)Qk+1​(u) are nonzero. This is the non-degeneracy the division form presupposes; it is imposed on the original system only. The standing assumption n>0n>0n>0 is kept as N<MN<MN<M, although the algebra of §4 does not use it. A1 is the Boolean condition ∣k∣≠∣k+1∣|k|\neq|k+1|∣k∣=∣k+1∣, and A2 is 2≤k2\le k2≤k, k+2≤dk+2\le dk+2≤d.

The reduced system is the same BAE predicate applied to the deleted grading on d−2d-2d−2 positions and the reindexed roots, with its own source terms and its own loop weight. A formalization that writes the reduced equations by hand, or passes nnn to the reduced chain as a parameter, is trivializing and is ruled out. Without the regularity hypothesis, Lean's convention x/0=0x/0=0x/0=0 would make degenerate configurations satisfy (2.9) vacuously; regularity excludes this, and a verification file checks that the hypotheses of the goal are jointly satisfiable and that regularity is not vacuous.

Out of scope: the Yang–Baxter and Yangian structure, the walled Brauer algebra, the weight constraints (4.1) and (4.8), existence and uniqueness of lifted type-kkk roots, inhomogeneous chains, the boundary case k=1,rk=1,rk=1,r of §4.3, and the thermodynamic limit. Proofs of the milestones are welcome, as are lemmas that put the finite-product manipulations of QQQ-polynomials into a reusable form.

Selected references

  • C. Candu, Continuum Limit of gl(M|N) Spin Chains, arXiv preprint (v1, 2010), JHEP 2011. https://arxiv.org/abs/1012.0050
  • S. Belliard and E. Ragoucy, Nested Bethe ansatz for 'all' closed spin chains, J. Phys. A 41, 295202 (2008). https://arxiv.org/abs/0804.2822
  • C. Candu, T. Creutzig, V. Mitev and V. Schomerus, Cohomological Reduction of Sigma Models, JHEP 05, 047 (2010). https://arxiv.org/abs/1001.1344
  • F. H. L. Eßler, H. Frahm and H. Saleur, Continuum Limit of the Integrable sl(2|1) 3–3̄ Superspin Chain, Nucl. Phys. B 712, 513 (2005). https://arxiv.org/abs/cond-mat/0501197
  • E. Ogievetsky and P. Wiegmann, Factorized S-Matrix and the Bethe Ansatz for Simple Lie Groups, Phys. Lett. B 168, 360 (1986).
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Information TheoryMathematical PhysicsQuantum Information·Captain: mikedeng1

Information-disturbance tradeoff in quantum measurement on the uniform ensemble and on the mutually unbiased bases: the square-root dynamics is least disturbing on the uniform ensembleResearch Paper

Motivation

Measuring a quantum system disturbs it. The information–disturbance tradeoff asks how little a measurement that yields a given amount of information about an unknown state must change that state. The question underlies the security analysis of quantum key distribution, where an eavesdropper's information gain is paid for in detectable disturbance, and the design of measurements that must leave a system usable afterwards, as in sequential or weak measurement schemes.

A measurement has two separate parts: the POVM, which fixes the outcome statistics, and the instrument, which fixes the post-measurement state for each outcome. Many instruments realize the same POVM. The natural candidate for the least disturbing one is the square-root (Lüders) dynamics, which maps a state ρ\rhoρ to Fb1/2ρFb1/2F_b^{1/2}\rho F_b^{1/2}Fb1/2​ρFb1/2​ on outcome bbb. Whether this candidate is in fact optimal depends on how disturbance is averaged. H. Barnum (2002) showed that it is optimal when the average is over the uniform ensemble of pure states, and computed the resulting minimal disturbance for every POVM (arXiv:quant-ph/0205155). For general ensembles the same paper leaves optimality open (its "Possibility 4").

Setting

Fix a dimension d≥1d\ge1d≥1 and the Hilbert space Cd\mathbb C^dCd with standard basis {∣i⟩}\{|i\rangle\}{∣i⟩}.

  • A POVM is a finite family {Fb}b∈B\{F_b\}_{b\in B}{Fb​}b∈B​ of positive semidefinite operators with ∑bFb=I\sum_bF_b=I∑b​Fb​=I. Outcome bbb occurs on state ρ\rhoρ with probability tr⁡ρFb\operatorname{tr}\rho F_btrρFb​.
  • An instrument compatible with {Fb}\{F_b\}{Fb​} is a finite family of operators {Abi}\{A_{bi}\}{Abi​} (Hellwig–Kraus, or HK, operators) with
∑iAbi†Abi=Fbfor every b.\sum_iA_{bi}^\dagger A_{bi}=F_b\quad\text{for every }b .i∑​Abi†​Abi​=Fb​for every b.

The unnormalized post-measurement state on outcome bbb is Ab(ρ)=∑iAbiρAbi†\mathcal A_b(\rho)=\sum_iA_{bi}\rho A_{bi}^\daggerAb​(ρ)=∑i​Abi​ρAbi†​, and the overall operation is A(ρ)=∑b,iAbiρAbi†\mathcal A(\rho)=\sum_{b,i}A_{bi}\rho A_{bi}^\daggerA(ρ)=∑b,i​Abi​ρAbi†​.

  • The square-root operation of the POVM is S(ρ)=∑bFb1/2ρFb1/2\mathcal S(\rho)=\sum_bF_b^{1/2}\rho F_b^{1/2}S(ρ)=∑b​Fb1/2​ρFb1/2​, the instrument with the single HK operator Fb1/2F_b^{1/2}Fb1/2​ per outcome. An instrument with one HK operator per outcome has one-term conditional dynamics.
  • The uniform ensemble Ω\OmegaΩ is the unitarily invariant probability measure on unit vectors of Cd\mathbb C^dCd, the law of U∣0⟩U|0\rangleU∣0⟩ for a Haar-random unitary UUU.
  • For a pure state the fidelity with an operator σ\sigmaσ is ⟨ψ∣σ∣ψ⟩\langle\psi|\sigma|\psi\rangle⟨ψ∣σ∣ψ⟩. The average fidelity of an operation E\mathcal EE is F‾(E)=∫dΩψ ⟨ψ∣E(∣ψ⟩⟨ψ∣)∣ψ⟩\overline F(\mathcal E)=\int d\Omega_\psi\,\langle\psi|\mathcal E(|\psi\rangle\langle\psi|)|\psi\rangleF(E)=∫dΩψ​⟨ψ∣E(∣ψ⟩⟨ψ∣)∣ψ⟩, and its average disturbance is
D(E)=1−F‾(E)=1−∫dΩψ∑b,i∣⟨ψ∣Abi∣ψ⟩∣2(E=A).D(\mathcal E)=1-\overline F(\mathcal E)=1-\int d\Omega_\psi\sum_{b,i}|\langle\psi|A_{bi}|\psi\rangle|^2\qquad(\mathcal E=\mathcal A).D(E)=1−F(E)=1−∫dΩψ​b,i∑​∣⟨ψ∣Abi​∣ψ⟩∣2(E=A).
  • The second moment of the ensemble is Π=∫dΩψ ∣ψ⟩⟨ψ∣⊗∣ψ⟩⟨ψ∣\Pi=\int d\Omega_\psi\,|\psi\rangle\langle\psi|\otimes|\psi\rangle\langle\psi|Π=∫dΩψ​∣ψ⟩⟨ψ∣⊗∣ψ⟩⟨ψ∣.

Formalization targets

The goal and the numbered milestones below are from Barnum, pp. 9–13, arXiv:quant-ph/0205155v1.

Goal: Theorem 5

For every POVM {Fb}\{F_b\}{Fb​} and every finite instrument {Abi}\{A_{bi}\}{Abi​} compatible with it,

D(S)  ≤  D(A).D(\mathcal S)\;\le\;D(\mathcal A).D(S)≤D(A).

The instrument may have several HK operators per outcome; this is what distinguishes Theorem 5 from Theorem 8.

Milestones

  1. Eq. (31) (Jones): for unit vectors a,ba,ba,b, ∫dΩψ∣⟨ψ∣a⟩∣2∣⟨ψ∣b⟩∣2=1+∣⟨a∣b⟩∣2d(d+1)\int d\Omega_\psi|\langle\psi|a\rangle|^2|\langle\psi|b\rangle|^2=\dfrac{1+|\langle a|b\rangle|^2}{d(d+1)}∫dΩψ​∣⟨ψ∣a⟩∣2∣⟨ψ∣b⟩∣2=d(d+1)1+∣⟨a∣b⟩∣2​.
  2. Lemma 9: Π=1d(d+1)∑i,j(∣i⟩⟨i∣⊗∣j⟩⟨j∣+∣i⟩⟨j∣⊗∣j⟩⟨i∣)\Pi=\dfrac{1}{d(d+1)}\sum_{i,j}\big(|i\rangle\langle i|\otimes|j\rangle\langle j|+|i\rangle\langle j|\otimes|j\rangle\langle i|\big)Π=d(d+1)1​∑i,j​(∣i⟩⟨i∣⊗∣j⟩⟨j∣+∣i⟩⟨j∣⊗∣j⟩⟨i∣).
  3. Eq. (32): ∫dΩψ⟨ψ∣A∣ψ⟩⟨ψ∣B∣ψ⟩=tr⁡Π(A⊗B)=1d(d+1)∑ij(⟨i∣A∣i⟩⟨j∣B∣j⟩+⟨i∣A∣j⟩⟨j∣B∣i⟩)\int d\Omega_\psi\langle\psi|A|\psi\rangle\langle\psi|B|\psi\rangle=\operatorname{tr}\Pi(A\otimes B)=\frac{1}{d(d+1)}\sum_{ij}\big(\langle i|A|i\rangle\langle j|B|j\rangle+\langle i|A|j\rangle\langle j|B|i\rangle\big)∫dΩψ​⟨ψ∣A∣ψ⟩⟨ψ∣B∣ψ⟩=trΠ(A⊗B)=d(d+1)1​∑ij​(⟨i∣A∣i⟩⟨j∣B∣j⟩+⟨i∣A∣j⟩⟨j∣B∣i⟩).
  4. Eq. (33): F‾(ρ↦∑kAkρAk†)=1d(d+1)∑k(∣tr⁡Ak∣2+tr⁡AkAk†)\overline F\big(\rho\mapsto\sum_kA_k\rho A_k^\dagger\big)=\frac{1}{d(d+1)}\sum_k\big(|\operatorname{tr}A_k|^2+\operatorname{tr}A_kA_k^\dagger\big)F(ρ↦∑k​Ak​ρAk†​)=d(d+1)1​∑k​(∣trAk​∣2+trAk​Ak†​).
  5. Trace bound (p. 13, cited from von Neumann): for A≥0A\ge0A≥0, max⁡V unitary∣tr⁡VA∣\max_{V\text{ unitary}}|\operatorname{tr}VA|maxV unitary​∣trVA∣ is attained where VA=A†AVA=\sqrt{A^\dagger A}VA=A†A​.
  6. Theorem 8: for one-term instruments, ∑bF‾b≤1d(d+1)(d+∑b(tr⁡Fb1/2)2)\sum_b\overline F_b\le\frac{1}{d(d+1)}\big(d+\sum_b(\operatorname{tr}F_b^{1/2})^2\big)∑b​Fb​≤d(d+1)1​(d+∑b​(trFb1/2​)2), with equality for the square-root dynamics.
  7. Theorem 7 (Ando): (A,B)↦At⊗B1−t(A,B)\mapsto A^t\otimes B^{1-t}(A,B)↦At⊗B1−t is jointly concave for 0≤t≤10\le t\le10≤t≤1.
  8. Proposition 6: ⟨ψ∣P1∣ψ⟩2+⟨ψ∣P2∣ψ⟩2≤⟨ψ∣P12+P22∣ψ⟩2\langle\psi|P_1|\psi\rangle^2+\langle\psi|P_2|\psi\rangle^2\le\langle\psi|\sqrt{P_1^2+P_2^2}|\psi\rangle^2⟨ψ∣P1​∣ψ⟩2+⟨ψ∣P2​∣ψ⟩2≤⟨ψ∣P12​+P22​​∣ψ⟩2 for positive P1,P2P_1,P_2P1​,P2​.
  9. Coarse-graining (p. 10): ∑j⟨ψ∣Pj∣ψ⟩2≤⟨ψ∣∑jPj2∣ψ⟩2\sum_j\langle\psi|P_j|\psi\rangle^2\le\langle\psi|\sqrt{\sum_jP_j^2}|\psi\rangle^2∑j​⟨ψ∣Pj​∣ψ⟩2≤⟨ψ∣∑j​Pj2​​∣ψ⟩2.

Significance

Theorem 5 together with Theorem 8 gives a closed form for the minimal disturbance on the uniform ensemble of every POVM: D‾min⁡=1−1d(d+1)(d+∑b(tr⁡Fb1/2)2)\overline D_{\min}=1-\frac{1}{d(d+1)}\big(d+\sum_b(\operatorname{tr}F_b^{1/2})^2\big)Dmin​=1−d(d+1)1​(d+∑b​(trFb1/2​)2) (Eqs. (34)–(35)). For rank-one POVMs this is (d−1)/(d+1)(d-1)/(d+1)(d−1)/(d+1), one endpoint of the information–disturbance frontier that the rest of the paper studies. The result also shows that on this ensemble, extra Kraus operators per outcome never reduce disturbance, so the frontier may be computed over square-root instruments alone.

The milestones are of independent use. Lemma 9 and Eq. (32) are the standard second-moment formula for Haar-random pure states (the 2-design property). Eq. (33) is the Kraus-operator form of the average fidelity that appears throughout quantum channel benchmarking. Ando's concavity theorem is equivalent to Lieb's concavity theorem.

The results are proved in the paper (2002). This mission formalizes them; to the extent known, none of the paper's statements has a machine-checked proof. The platform already has the uniform ensemble and the average fidelity as published definitions, and Nielsen's formula relating average and entanglement fidelity, which is a different statement.

Difficulty

The polar-decomposition step suggests a pointwise argument: write Abi=UbiPbiA_{bi}=U_{bi}P_{bi}Abi​=Ubi​Pbi​ and replace UbiU_{bi}Ubi​ by III. That fails. For a fixed ψ\psiψ, ∣⟨ψ∣UP∣ψ⟩∣2|\langle\psi|UP|\psi\rangle|^2∣⟨ψ∣UP∣ψ⟩∣2 can exceed ⟨ψ∣P∣ψ⟩2\langle\psi|P|\psi\rangle^2⟨ψ∣P∣ψ⟩2 (take d=2d=2d=2, P=∣0⟩⟨0∣P=|0\rangle\langle0|P=∣0⟩⟨0∣, ψ=(∣0⟩+∣1⟩)/2\psi=(|0\rangle+|1\rangle)/\sqrt2ψ=(∣0⟩+∣1⟩)/2​, U∣0⟩=ψU|0\rangle=\psiU∣0⟩=ψ). The replacement is valid only after averaging over Ω\OmegaΩ, through the explicit fourth-moment computation of Lemma 9. The second obstacle is merging several HK operators of one outcome into one, which needs Proposition 6. Proposition 6 is an inequality between non-commuting operators. The commuting case is elementary, but the general case rests on Ando's joint concavity, an operator-concavity theorem of Lieb's type that is not in Mathlib.

Formalization scope

Operators are Matrix (Fin d) (Fin d) ℂ and vectors EuclideanSpace ℂ (Fin d), with 0 < d. The uniform ensemble is the published QAlgorithms.QuditFidelity.haarPureStateLaw d hd, the image of normalized Haar measure on the unitary group under U↦U∣0⟩U\mapsto U|0\rangleU↦U∣0⟩. The average fidelity is the published averageFidelity d hd, whose integrand is Re⁡tr⁡(∣ψ⟩⟨ψ∣ E(∣ψ⟩⟨ψ∣))\operatorname{Re}\operatorname{tr}\big(|\psi\rangle\langle\psi|\,\mathcal E(|\psi\rangle\langle\psi|)\big)Retr(∣ψ⟩⟨ψ∣E(∣ψ⟩⟨ψ∣)). Disturbance is 1 - averageFidelity. POVMs are QAlgorithms.IsPOVM on a finite outcome type. An instrument is A : B → I → Matrix with one finite Kraus index type I for every outcome. Outcomes with fewer operators are padded with zeros, which changes neither the compatibility condition nor the operation. The square root is cfc Real.sqrt. Real powers in Theorem 7 use cfc of Real.rpow, so X0=IX^0=IX0=I. Real-valued quadratic forms and traces of positive operators are taken as real parts. Π\PiΠ is defined entrywise.

The goal must not be read with I = Unit. That would be Theorem 8's one-term case, and the goal quantifies over every finite I. The ensemble is the Haar image itself, not a measure assumed to have the second moment of Lemma 9.

The wrapper disturbance accepts a raw superoperator, for which an integral need not exist. Every theorem here applies it only to a finite Kraus map, whose integrand is continuous and integrable on the Haar ensemble. A complete development needs Haar moment integrals on the unitary group (reusable for any unitary-design argument), the polar decomposition and the trace inequality for matrices, and an operator-concavity theorem (Ando/Lieb). Contributions of any of these, or of the commuting-case proof of Proposition 6 as a stepping stone, are welcome.

Selected references

  • H. Barnum, Information-disturbance tradeoff in quantum measurement on the uniform ensemble, preprint, 2002. arXiv:quant-ph/0205155
  • T. Ando, Concavity of certain maps on positive definite matrices and applications to Hadamard products, Linear Algebra Appl. 26 (1979) 203–241. doi:10.1016/0024-3795(79)90179-4
  • E. H. Lieb, Convex trace functions and the Wigner–Yanase–Dyson conjecture, Adv. Math. 11 (1973) 267–288. doi:10.1016/0001-8708(73)90011-X
  • M. A. Nielsen, A simple formula for the average gate fidelity of a quantum dynamical operation, Phys. Lett. A 303 (2002) 249–252. arXiv:quant-ph/0205035
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Generalized Kraus Operators and Generators of Quantum Dynamical Semigroups: Matrix Normality Is Equivalent to a Generalized Standard Form of the GeneratorResearch Paper

Motivation

The time evolution of an open quantum system with no memory effects is described by a quantum dynamical semigroup (QDS): a family Tt\mathcal T^tTt, t≥0t\ge0t≥0, of completely positive, trace preserving maps on the density operators of a Hilbert space H\mathcal HH, with Ts+t=TsTt\mathcal T^{s+t}=\mathcal T^s\mathcal T^tTs+t=TsTt. Radiative decay, diffusion and dissipative state preparation are all modelled this way. For semigroups that are continuous in operator norm, Gorini, Kossakowski and Sudarshan (GKS76) and Lindblad (L76) showed in 1976 that the generator always has the form

L(ρ)=∑kLkρLk∗−Mρ−ρM∗,∑kLk∗Lk=M+M∗,\mathcal L(\rho)=\sum_k L_k\rho L_k^*-M\rho-\rho M^*,\qquad \sum_k L_k^*L_k=M+M^*,L(ρ)=k∑​Lk​ρLk∗​−Mρ−ρM∗,k∑​Lk∗​Lk​=M+M∗,

with bounded operators LkL_kLk​, MMM. Most physical generators are unbounded, and the corresponding semigroups are only strongly continuous. Davies (D77) introduced a "standard form" for such generators under additional assumptions, and Holevo (H97) and Fagnola extended the analysis. Holevo also exhibited generators that are not of standard form. Which strongly continuous QDS have a Lindblad-type generator built from Hilbert-space operators has therefore remained a structural question.

Alazzawi and Baumgartner (arXiv:1306.4531) answer it for trace preserving semigroups with a single condition, matrix normality, and prove an infinite-dimensional, unbounded version of the Kraus representation of completely positive maps along the way.

Setting

H\mathcal HH is a separable complex Hilbert space with inner product ⟨⋅∣⋅⟩\langle\cdot|\cdot\rangle⟨⋅∣⋅⟩, conjugate-linear in the first slot. T(H)\mathfrak T(\mathcal H)T(H) is the space of trace-class operators with the trace norm ∥⋅∥1\|\cdot\|_1∥⋅∥1​, and ∣φ⟩⟨ψ∣|\varphi\rangle\langle\psi|∣φ⟩⟨ψ∣ is the rank-one operator x↦⟨ψ∣x⟩φx\mapsto\langle\psi|x\rangle\varphix↦⟨ψ∣x⟩φ. The semigroup Tt\mathcal T^tTt acts on T(H)\mathfrak T(\mathcal H)T(H), is completely positive and trace preserving, and is strongly continuous: ∥Tt(ρ)−ρ∥1→0\|\mathcal T^t(\rho)-\rho\|_1\to0∥Tt(ρ)−ρ∥1​→0 as t↓0t\downarrow0t↓0. Its generator is

L(ρ)=lim⁡t↓01t(Tt(ρ)−ρ),\mathcal L(\rho)=\lim_{t\downarrow0}\tfrac1t\big(\mathcal T^t(\rho)-\rho\big),L(ρ)=t↓0lim​t1​(Tt(ρ)−ρ),

the limit taken in trace norm, on the domain D(L)\mathcal D(\mathcal L)D(L) where it exists. A set S⊆D(L)S\subseteq\mathcal D(\mathcal L)S⊆D(L) is a core if its closure in the graph norm ∥ρ∥1+∥L(ρ)∥1\|\rho\|_1+\|\mathcal L(\rho)\|_1∥ρ∥1​+∥L(ρ)∥1​ is all of D(L)\mathcal D(\mathcal L)D(L).

For an orthonormal basis {ek}\{e_k\}{ek​} write De=lin⁡{ek}\mathcal D_e=\operatorname{lin}\{e_k\}De​=lin{ek​} and De2=lin⁡{∣ek⟩⟨eℓ∣}\mathcal D_e^2=\operatorname{lin}\{|e_k\rangle\langle e_\ell|\}De2​=lin{∣ek​⟩⟨eℓ​∣}. The QDS is matrix normal if De2\mathcal D_e^2De2​ is a core for L\mathcal LL for some basis. It is not enough that De2⊆D(L)\mathcal D_e^2\subseteq\mathcal D(\mathcal L)De2​⊆D(L): the paper's example is the Dirichlet Laplacian on an interval.

A generalized standard form of L\mathcal LL consists of operators LkL_kLk​ (countably many) and MMM on H\mathcal HH, densely defined, with the following properties. MMM is closed and −M-M−M generates a strongly continuous semigroup on H\mathcal HH. Each LkL_kLk​ is defined on D(M)\mathcal D(M)D(M) and is relatively bounded with respect to MMM. For all φ,ψ∈D(M)\varphi,\psi\in\mathcal D(M)φ,ψ∈D(M),

L(∣φ⟩⟨ψ∣)=∑k∣Lkφ⟩⟨Lkψ∣−∣Mφ⟩⟨ψ∣−∣φ⟩⟨Mψ∣,∑k∥Lkφ∥2=⟨φ∣Mφ⟩+⟨Mφ∣φ⟩.\mathcal L(|\varphi\rangle\langle\psi|)=\sum_k|L_k\varphi\rangle\langle L_k\psi|-|M\varphi\rangle\langle\psi|-|\varphi\rangle\langle M\psi|,\qquad \sum_k\|L_k\varphi\|^2=\langle\varphi|M\varphi\rangle+\langle M\varphi|\varphi\rangle .L(∣φ⟩⟨ψ∣)=k∑​∣Lk​φ⟩⟨Lk​ψ∣−∣Mφ⟩⟨ψ∣−∣φ⟩⟨Mψ∣,k∑​∥Lk​φ∥2=⟨φ∣Mφ⟩+⟨Mφ∣φ⟩.

Finally, the finite sums D0\mathcal D_0D0​ of such dyads form a core for L\mathcal LL. This is the paper's Definition 1, written in its own adjoint-free form (19)–(20).

Formalization targets

Goal: Theorem 3

L has a generalized standard form  ⟺  the QDS is matrix normal,\mathcal L\ \text{has a generalized standard form}\iff\text{the QDS is matrix normal},L has a generalized standard form⟺the QDS is matrix normal,

and then De⊆D(M)\mathcal D_e\subseteq\mathcal D(M)De​⊆D(M): every basis that witnesses matrix normality carries a standard form whose MMM contains De\mathcal D_eDe​ in its domain.

Milestones

The direction from matrix normality to the standard form (§3.1) runs through the following statements:

  • the trace identity Tr⁡L(ρ)=0\operatorname{Tr}\mathcal L(\rho)=0TrL(ρ)=0 (9);
  • the positivity properties of L\mathcal LL on De\mathcal D_eDe​ (Lemma 4);
  • complete positivity of the expander L+(ρ)=L(ρ)+Mρ+ρM†\mathcal L_+(\rho)=\mathcal L(\rho)+M\rho+\rho M^\daggerL+​(ρ)=L(ρ)+Mρ+ρM† for the "mover-and-contractor" Mψ=−L(∣ψ⟩⟨χ∣)χ+12⟨χ∣L(∣χ⟩⟨χ∣)∣χ⟩ψM\psi=-\mathcal L(|\psi\rangle\langle\chi|)\chi+\tfrac12\langle\chi|\mathcal L(|\chi\rangle\langle\chi|)|\chi\rangle\psiMψ=−L(∣ψ⟩⟨χ∣)χ+21​⟨χ∣L(∣χ⟩⟨χ∣)∣χ⟩ψ (Definition 5, Proposition 6);
  • the generalized Kraus theorem for completely positive maps from De2\mathcal D_e^2De2​ into quadratic forms (Theorem 14, Corollary 16);
  • the identity ∑k∥Lkφ∥2=⟨φ∣Mφ⟩+⟨Mφ∣φ⟩\sum_k\|L_k\varphi\|^2=\langle\varphi|M\varphi\rangle+\langle M\varphi|\varphi\rangle∑k​∥Lk​φ∥2=⟨φ∣Mφ⟩+⟨Mφ∣φ⟩ on De\mathcal D_eDe​ (proof of (4));
  • closedness of MMM (Proposition 7);
  • generation of a contraction semigroup e−tMe^{-tM}e−tM (Proposition 8).

The converse direction (§3.2) consists of:

  • the domination 0≤Tr⁡L+(ρ)=Tr⁡M(ρ)≤∥M(ρ)∥10\le\operatorname{Tr}\mathcal L_+(\rho)=\operatorname{Tr}\mathcal M(\rho)\le\|\mathcal M(\rho)\|_10≤TrL+​(ρ)=TrM(ρ)≤∥M(ρ)∥1​ (p. 9);
  • the Cauchy–Schwarz bound of Lemma 10;
  • the graph-norm approximation estimates of Lemma 11, with the constant ε(∥φ∥+∥Mφ∥+∥ψ∥+∥Mψ∥+2ε)\varepsilon(\|\varphi\|+\|M\varphi\|+\|\psi\|+\|M\psi\|+2\varepsilon)ε(∥φ∥+∥Mφ∥+∥ψ∥+∥Mψ∥+2ε);
  • the construction of a basis with De\mathcal D_eDe​ a core for MMM and De2\mathcal D_e^2De2​ a core for L\mathcal LL (Proposition 12).

Significance

Theorem 3 identifies the trace preserving QDS whose generators admit a Lindblad-type description by Hilbert-space operators: they are exactly those determined by their action on the matrix units of a basis. Matrix normality is a condition on matrix elements, which can be checked from the differential equations that physical models provide. The standard form is the structure that dilation, stochastic-unravelling and conservativity results take as their input. Theorem 14 is of independent use: it is a Kraus decomposition, with no boundedness assumption, for completely positive maps into quadratic forms in infinite dimension.

The results are proved in the paper. None of them has a machine-checked proof that we know of. The finite-dimensional Choi-to-Kraus theorem is formalized on Prove2Me; the unbounded, form-valued version and the generator characterization are not. The mission formalizes the statements of §§2–3 and the Appendix exactly as printed. A faithful formal proof also has to settle the steps the paper only asserts: why the LkL_kLk​ extend uniquely from De\mathcal D_eDe​ to D(M)\mathcal D(M)D(M), and why (3) and the core property extend to all of D0\mathcal D_0D0​.

Difficulty

Every operator in the standard form may be unbounded. The adjoints Lk†L_k^\daggerLk†​ and M†M^\daggerM† are in general only "generalized operators" into an algebraic dual, so the familiar identities Tr⁡(LρL∗)=∥Lφ∥2\operatorname{Tr}(L\rho L^*)=\|L\varphi\|^2Tr(LρL∗)=∥Lφ∥2 cannot be used as written. The obvious route, applying the Stinespring or Kraus theorem to L+\mathcal L_+L+​, fails because L+\mathcal L_+L+​ is neither bounded nor defined on all of T(H)\mathfrak T(\mathcal H)T(H). The Choi matrix ∑ijEij⊗Eij\sum_{ij}E_{ij}\otimes E_{ij}∑ij​Eij​⊗Eij​ is itself only a quadratic form in infinite dimension, so the Kraus operators cannot be read off from a square root of a Choi operator. On the other side, the converse direction needs core arguments in two graph norms at once, on H\mathcal HH for MMM and on T(H)\mathfrak T(\mathcal H)T(H) for L\mathcal LL.

Formalization scope

The trace class, trace norm and trace come from the published definitions QAlgorithms_Papers_Independent_Dependency50_P13, the semigroup and its trace-norm generator graph from QAlgorithms_Papers_Independent_Next46_P09, and contraction semigroups on H\mathcal HH from QAlgorithms_Papers_Independent_Claimed50_P50. The local module GenKraus.StdForm.Setting defines:

  • trace preservation and strong continuity of the semigroup;
  • dyads, De2\mathcal D_e^2De2​, cores and matrix normality (Definition 2);
  • the generalized standard form (Definition 1, through (19)–(20));
  • the operator MMM of Definition 5 and the expander (8);
  • M\mathcal MM on dyads (15);
  • form-valued completely positive maps (Theorem 14).

The formalization commits to the following conventions:

  • A basis is an orthonormal set with dense span.
  • The index set of the LkL_kLk​ and of the Kraus operators is a countable type, finite allowed.
  • Kraus sums converge in trace norm along finite subsets in (3), and as unconditional scalar sums in (4) and (23).
  • "MMM generates a semigroup" assumes no contractivity; contractivity is the conclusion of Proposition 8.
  • Generator statements are stated through the graph relation, so no value of L\mathcal LL is chosen off its domain.
  • Trace norms are applied only to trace-class operators.
  • Theorem 14 indexes both bases by N\mathbb NN, which is the paper's infinite dimension.

A formalization in which De2⊆D(L)\mathcal D_e^2\subseteq\mathcal D(\mathcal L)De2​⊆D(L) replaces the core condition, (4) is weakened to an inequality, or the core clause of Definition 1 is dropped, states a different and weaker theorem. These are excluded.

Corollary 17 (trace preserving QQQ gives bounded Kraus operators) is not used for Theorem 3 and is not included, and the two physical examples of §5 are illustrations without numbered claims. Contributions toward reusable infrastructure are welcome: generator cores, relatively bounded perturbations, the Lumer–Phillips theorem on Hilbert space, and Gram realizations of positive kernels.

Selected references

  • S. Alazzawi, B. Baumgartner, Generalized Kraus Operators and Generators of Quantum Dynamical Semigroups, arXiv:1306.4531v4, 2015; Rev. Math. Phys. https://arxiv.org/abs/1306.4531
  • G. Lindblad, On the Generators of Quantum Dynamical Semigroups, Commun. Math. Phys. 48, 119–130, 1976. https://doi.org/10.1007/BF01608499
  • V. Gorini, A. Kossakowski, E. C. G. Sudarshan, Completely positive dynamical semigroups of N-level systems, J. Math. Phys. 17, 821–825, 1976. https://doi.org/10.1063/1.522979
  • E. B. Davies, Quantum Dynamical Semigroups and the Neutron Diffusion Equation, Rep. Math. Phys. 11, 169–188, 1977. https://doi.org/10.1016/0034-4877(77)90059-3
  • A. S. Holevo, Covariant Quantum Dynamical Semigroups: Unbounded Generators, 1997. https://arxiv.org/abs/quant-ph/9701037
  • K. Kraus, General State Changes in Quantum Theory, Ann. Phys. 64, 311–335, 1971. https://doi.org/10.1016/0003-4916(71)90108-4
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Amplification of NOON States: Fock-Basis Density Matrix of a Symmetrically Amplified NOON State at Arbitrary GainResearch Paper

Motivation

NOON states, 12(∣N,0⟩+∣0,N⟩)\tfrac{1}{\sqrt2}(|N,0\rangle + |0,N\rangle)2​1​(∣N,0⟩+∣0,N⟩), put NNN photons into one of two optical modes in coherent superposition. They are the standard example of a non-Gaussian, maximally path-entangled state of light and the resource behind phase estimation at the Heisenberg limit (Dowling, Contemp. Phys. 49, 2008). They are also fragile: they are hard to prepare with large NNN and are degraded by loss and noise. A natural question is what happens when such a state is sent through a phase-insensitive amplifier, the device that compensates loss but must add noise by the laws of quantum mechanics (Caves, Phys. Rev. D 26, 1982).

G. S. Agarwal, S. Chaturvedi and A. Rai (arXiv:0912.5134, 2009) answer this question in closed form. For amplification of both modes with the same gain they derive the exact density matrix of the output for every gain, show that it is a two-mode photon-added thermal state, and use it to follow the entanglement of the amplified state. An earlier study by Agarwal and Chaturvedi (arXiv:0906.2743, 2009, the paper's ref. [9]) had found the gains at which Gaussian two-mode squeezed states lose their entanglement under the same amplifier; the NOON computation is the non-Gaussian counterpart.

Setting

Two bosonic modes aaa and bbb have the number basis ∣n,m⟩|n,m\rangle∣n,m⟩, n,m∈Nn,m\in\mathbb Nn,m∈N (nnn photons in aaa, mmm in bbb). An operator XXX on the two-mode Fock space ℓ2(N×N)\ell^2(\mathbb N\times\mathbb N)ℓ2(N×N) is described by its matrix ⟨p∣X∣q⟩\langle p|X|q\rangle⟨p∣X∣q⟩. For an integer N≥1N\ge1N≥1 the input is

ρin=∣NOON⟩⟨NOON∣,∣NOON⟩=12(∣N,0⟩+∣0,N⟩).\rho_{\mathrm{in}} = |\mathrm{NOON}\rangle\langle\mathrm{NOON}|,\qquad |\mathrm{NOON}\rangle = \tfrac1{\sqrt2}\big(|N,0\rangle+|0,N\rangle\big).ρin​=∣NOON⟩⟨NOON∣,∣NOON⟩=2​1​(∣N,0⟩+∣0,N⟩).

The amplifier of amplitude gain G>1G>1G>1 acts on one mode through the Kraus operators Aℓ(G)A_\ell(G)Aℓ​(G), ℓ∈N\ell\in\mathbb Nℓ∈N, the weighted raising shifts

⟨n+ℓ∣Aℓ(G)∣n⟩=1G(n+ℓℓ)(1−1G2)ℓ/2G−n,\langle n+\ell|A_\ell(G)|n\rangle = \frac1G\sqrt{\binom{n+\ell}{\ell}}\Big(1-\frac1{G^2}\Big)^{\ell/2}G^{-n},⟨n+ℓ∣Aℓ​(G)∣n⟩=G1​(ℓn+ℓ​)​(1−G21​)ℓ/2G−n,

with all other entries zero. Symmetric amplification applies it to both modes:

ΦG(ρ)=∑ℓ,ℓ′=0∞(Aℓ(G)⊗Aℓ′(G)) ρ (Aℓ(G)⊗Aℓ′(G))†,\Phi_G(\rho) = \sum_{\ell,\ell'=0}^\infty \big(A_\ell(G)\otimes A_{\ell'}(G)\big)\,\rho\,\big(A_\ell(G)\otimes A_{\ell'}(G)\big)^\dagger ,ΦG​(ρ)=ℓ,ℓ′=0∑∞​(Aℓ​(G)⊗Aℓ′​(G))ρ(Aℓ​(G)⊗Aℓ′​(G))†,

the series converging in trace norm. The paper describes states also by the Q function Q(α,β)=π−2⟨α,β∣ρ∣α,β⟩Q(\alpha,\beta) = \pi^{-2}\langle\alpha,\beta|\rho|\alpha,\beta\rangleQ(α,β)=π−2⟨α,β∣ρ∣α,β⟩, where ∣α,β⟩|\alpha,\beta\rangle∣α,β⟩ is the two-mode coherent state. The amplified two-mode vacuum is the product thermal state

ρG=1G4e−β(a†a+b†b),β=ln⁡G2G2−1,\rho_G = \frac1{G^4}e^{-\beta(a^\dagger a+b^\dagger b)},\qquad \beta=\ln\frac{G^2}{G^2-1},ρG​=G41​e−β(a†a+b†b),β=lnG2−1G2​,

and a†Na^{\dagger N}a†N, aNa^NaN (and b†Nb^{\dagger N}b†N, bNb^NbN) are the NNN-th powers of the creation and annihilation operators.

Formalization targets

Goal: the number-basis output, (17)

ΦG(ρin)=12N!G2N+4∑n,m=0∞(G2−1G2)n+m[(n+N)!n!∣n+N,m⟩⟨n+N,m∣+(m+N)!m!∣n,m+N⟩⟨n,m+N∣+(n+N)!n!(m+N)!m!(∣n+N,m⟩⟨n,m+N∣+∣n,m+N⟩⟨n+N,m∣)],\Phi_G(\rho_{\mathrm{in}}) = \frac{1}{2N!G^{2N+4}}\sum_{n,m=0}^\infty\Big(\frac{G^2-1}{G^2}\Big)^{n+m}\Big[\tfrac{(n+N)!}{n!}|n{+}N,m\rangle\langle n{+}N,m| + \tfrac{(m+N)!}{m!}|n,m{+}N\rangle\langle n,m{+}N| + \sqrt{\tfrac{(n+N)!}{n!}\tfrac{(m+N)!}{m!}}\big(|n{+}N,m\rangle\langle n,m{+}N| + |n,m{+}N\rangle\langle n{+}N,m|\big)\Big],ΦG​(ρin​)=2N!G2N+41​n,m=0∑∞​(G2G2−1​)n+m[n!(n+N)!​∣n+N,m⟩⟨n+N,m∣+m!(m+N)!​∣n,m+N⟩⟨n,m+N∣+n!(n+N)!​m!(m+N)!​​(∣n+N,m⟩⟨n,m+N∣+∣n,m+N⟩⟨n+N,m∣)],

for all N≥1N\ge1N≥1 and G>1G>1G>1, together with the facts that the output series converges in trace norm and that its limit is a density operator. This is the paper's main analytic result.

Milestones, in the order of the paper

  1. (11)–(12), the input Q function: Qin(α,β)=12N!π2∣αN+βN∣2e−(∣α∣2+∣β∣2)Q_{\mathrm{in}}(\alpha,\beta) = \frac{1}{2N!\pi^2}|\alpha^N+\beta^N|^2e^{-(|\alpha|^2+|\beta|^2)}Qin​(α,β)=2N!π21​∣αN+βN∣2e−(∣α∣2+∣β∣2), with ρin\rho_{\mathrm{in}}ρin​ written as a photon-added vacuum.
  2. (13), the output Q function: Qout(α,β)=G−4Qin(α/G,β/G)Q_{\mathrm{out}}(\alpha,\beta) = G^{-4}Q_{\mathrm{in}}(\alpha/G,\beta/G)Qout​(α,β)=G−4Qin​(α/G,β/G), in closed form.
  3. (8)+(16), two-mode: ΦG(∣0,0⟩⟨0,0∣)=ρG=G−4∑n,m(G2−1G2)n+m∣n,m⟩⟨n,m∣\Phi_G(|0,0\rangle\langle0,0|) = \rho_G = G^{-4}\sum_{n,m}\big(\frac{G^2-1}{G^2}\big)^{n+m}|n,m\rangle\langle n,m|ΦG​(∣0,0⟩⟨0,0∣)=ρG​=G−4∑n,m​(G2G2−1​)n+m∣n,m⟩⟨n,m∣.
  4. (14)/(15): ΦG(ρin)=12N!G2N{a†N+b†N}ρG{aN+bN}\Phi_G(\rho_{\mathrm{in}}) = \frac{1}{2N!G^{2N}}\{a^{\dagger N}+b^{\dagger N}\}\rho_G\{a^N+b^N\}ΦG​(ρin​)=2N!G2N1​{a†N+b†N}ρG​{aN+bN}.

Significance

The result. Formula (17) gives every matrix element of the amplified NOON state at every gain. It identifies the output as a photon-added thermal state in which either mode carries the NNN added photons, a family studied for single modes by Agarwal and Tara (Phys. Rev. A 46, 1992). The paper computes the partial transpose (18) of this matrix to obtain the logarithmic negativity of the amplified state as a function of gain (its Fig. 1), and observes that the zeros of the Q function, a signature of nonclassicality, survive amplification.

Formalizing it. The result is proved in the paper, by a phase-space argument; it has no machine-checked proof. A formal proof certifies the constants, the index shifts and the convergence of the infinite series, which the paper does not discuss, and produces a reusable two-mode layer (matrices, Kraus sums, coherent states, Q functions, photon addition) on top of the published single-mode Fock-space definitions.

Difficulty

The paper's route goes through the Q function: (13) is read off from the single-mode scaling law Qout(α)=G−2Qin(α/G)Q_{\mathrm{out}}(\alpha)=G^{-2}Q_{\mathrm{in}}(\alpha/G)Qout​(α)=G−2Qin​(α/G), and the density matrix (14) is then recognized from its Q function. The last step uses that a Q function determines the density operator, an analytic-continuation fact that is not in Mathlib, and neither step addresses convergence. The goal is a statement about a double infinite sum of operators in trace norm, not only about matrix entries: entrywise agreement of matrices does not by itself give trace-norm convergence of the Kraus series, nor that its limit is a positive, trace-one operator.

Formalization scope

  • Picture. Everything is stated with two-mode number-basis matrices, mode aaa first: bipartiteKet (n, m) is ∣n,m⟩|n,m\rangle∣n,m⟩. Operators come from the published module QAlgorithms_Papers_Independent_Dependency50_P39 (Fock spaces as ℓ2\ell^2ℓ2, bounded operators, trace class, trace-norm summation TraceHasSum, densities, the amplifier matrix, coherent coefficients), which is referenced and not redefined.
  • The channel. The paper models the amplifier by a master equation at η→0\eta\to0η→0 and uses it only through its Q action. The mission uses the quantum-limited amplifier in Kraus form; that its single-mode Q action is exactly the paper's (7) is the open platform theorem Dependency50.P39.amplifierHusimiScaling. The single-mode amplified vacuum (8) is part of the open Dependency50.P39.amplifierInputExamples; neither is posed again here.
  • Conventions. The Q function carries 1/π1/\pi1/π per mode, as in (5) and (12). Creation and annihilation operators are unbounded and appear only as index shifts of matrices with factor r!/(r−N)!\sqrt{r!/(r-N)!}r!/(r−N)!​. The hypotheses N≥1N\ge1N≥1 (normalization of the NOON vector) and G>1G>1G>1 (the paper's G=e(N1−N2)κtG=e^{(N_1-N_2)\kappa t}G=e(N1​−N2​)κt, needed for β\betaβ) are stated explicitly.
  • No trivial readings. Operators defined from matrices fall back to zero when no bounded realization exists, so every statement concludes the realization it uses, the trace-norm convergence and the density property; the output is the Kraus sum of the fixed amplifier family, and the matrix (17) is defined by its closed form, not through the channel.
  • Not formalized. The logarithmic negativity of input and output ((9)–(10), (18), Fig. 1), the zero-preservation remark, the asymmetric amplifier ((19)–(23), Fig. 2), the photon-added squeezed vacuum ((24)–(27)), and the master equation (2) with its Q-function equation (6).
  • Welcome contributions. Proofs of the milestones, the two-mode realization lemmas (bounded tensor-product Kraus operators, coherent vectors), and a proof of the open single-mode scaling law (7).

Selected references

  • G. S. Agarwal, S. Chaturvedi, A. Rai, Amplification of NOON States, arXiv preprint, 2009. https://arxiv.org/abs/0912.5134v1
  • G. S. Agarwal, S. Chaturvedi, arXiv preprint (entanglement-breaking gains of the phase-insensitive amplifier for two-mode squeezed states), 2009; ref. [9] of the paper. https://arxiv.org/abs/0906.2743
  • G. S. Agarwal, K. Tara, Nonclassical character of states exhibiting no squeezing or sub-Poissonian statistics, Phys. Rev. A 46, 485, 1992. https://doi.org/10.1103/PhysRevA.46.485
  • C. M. Caves, Quantum limits on noise in linear amplifiers, Phys. Rev. D 26, 1817, 1982. https://doi.org/10.1103/PhysRevD.26.1817
  • J. P. Dowling, Quantum optical metrology – the lowdown on high-N00N states, Contemp. Phys. 49, 125, 2008. https://doi.org/10.1080/00107510802091298
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Quantum Information·Captain: Goku

The Security of Practical Quantum Key DistributionResearch Paper

Motivation

Quantum key distribution (QKD) is the first quantum information task to reach the level of mature technology, already fit for commercialization. It aims at the creation of a secret key between authorized partners connected by a quantum channel and a classical authenticated channel. The security of the key can in principle be guaranteed without putting any restriction on the eavesdropper's power. The first two sections provide a concise up-to-date review of QKD, biased toward the practical side. The rest of the paper presents the essential theoretical tools that have been developed to assess the security of the main experimental platforms (discrete variables, continuous variables and distributed-phase-reference protocols).

This mission is the statement-level formalization of The Security of Practical Quantum Key Distribution (arXiv:0802.4155v3). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

15 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is I.B.5: intercept-resend information and disturbance (I.B.5: intercept-resend information and disturbance, PDF p. 5). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

28 results of the paper are not stated yet, because the library lacks an interface they need:

  • Paper seed, p.1: practical BB84 without decoy states, IV.B.2, Eq.(31): Operational tagged/squashed no-decoy BB84 extraction against all compatible attacks (hard)
  • II.C.3: schematic finite-key bound, Eq.(7): Printed schematic claim: Prob[||rho_KE-tau_K tensor rho_E||_1>2epsilon] is bounded up to omitted constants by exp(ell-F(rho_KE,epsilon)). (source-ambiguity)
  • II.E.1: phase randomization yields Poisson photon statistics, Eqs.(11)–(13): Normalized full-Fock coherent states and trace-class phase-average equality (hard)
  • III.B.2.a: one-way individual-attack bound, Eqs.(21)–(22): Uniform-over-compatible individual-attack one-way EC–PA achievability (hard)
  • III.B.2.b: one-way collective-attack bound, Eqs.(21),(23),(24): Uniform ccq direct/reverse extraction with half trace-distance security (hard)
  • IV.B.1: BB84 photon components and optimized privacy cost, Eq.(28): Constructed photon-tagged attack states, Holevo extrema and attaining attacks (hard)
  • IV.B.3: exact-parameter decoy BB84 rate and summation, Eqs.(33)–(34): Operational separately processed class extraction including vacuum contribution (hard)
  • IV.B.5: safe-source EB conservative multipair bound, Eqs.(40)–(42): Safe-SPDC multipair tagging and evaluated extraction (hard)
  • IV.B.5: EB qubit rate from a basis-independent source, Eq.(43): Basis-independent uncharacterized source to secure evaluated protocol (hard)
  • IV.C.2: calibrated decoy upper estimate, Eq.(50): Restricted calibrated-attack upper estimate with operational comparison (hard)
  • IV.C.2: calibrated no-decoy upper estimate, Eqs.(51)–(52): Feasible inferred calibrated parameters and restricted-attack upper comparison (hard)
  • V.B.3: Gaussian conditional variance and mutual information, Eqs.(60)–(61): Physical Gaussian experiment and actual mutual information (hard)
  • V.B.4: Eve–Alice conditional-variance tradeoff, Eqs.(62)–(65): Purification-conditioned quadrature variances and minimizing ensemble (hard)
  • V.B.4: reverse-reconciled individual-attack rate, Eq.(66): Gaussian individual-attack rate and saturating entanglement-cloner construction (hard)
  • V.B.4: qualitative high-loss / large-modulation noise tolerance: Source reports positivity in a high-loss (t*eta -> 0), large-modulation (v -> infinity) regime when epsilon<1/2. (source-ambiguity)
  • V.B.5: computed collective Gaussian Holevo information, Eqs.(67)–(68): Actual Gaussian output and conditioned state entropies (hard)
  • V.B.5: Gaussian-modulated homodyne collective security, Eq.(69): Gaussian extremality plus operational reverse-reconciled extraction (hard)
  • V.B.6: conditioned binary-channel postselection, Eqs.(70)–(71): Announcement-conditioned Gaussian instrument and averaged EC–PA extraction (hard)
  • VI.B.1: coherent beam-splitting attack and output states: Vacuum beam-splitter isometry on full Fock spaces (hard)
  • VI.B.1: DPS beam-splitting Holevo information and rate, Eqs.(73)–(74): Full-Fock two-pulse conditional mixtures and their Holevo spectra (hard)
  • VI.B.1: COW beam-splitting Holevo information and rate, Eqs.(75)–(76): Two-mode coherent/vacuum key states and their Holevo information (hard)
  • VI.B.2: restricted two-pulse COW upper estimate, Eqs.(77)–(78): Reported restricted-family expression: xi=2sqrt[V(1-V)]. If exp(-mu)<=xi, I_E=1; otherwise I_E=epsilon+(1-epsilon)h((1+F_V(mu))/2), F_V=(2V-1)exp(-mu)-xisqrt(1-exp(-2mu)). K=R*(1-I_E-leak_EC(Q)), R=nu_tilde*(mutt_B*eta+2p_d). (source-ambiguity)
  • VII.A–B: numerical platform and calibration comparisons: Figures 4–6 compare optimized K/nu_S for specified Table II parameter sets. BB84 curves are unconditional bounds under IV’s assumptions; CV curves concern collective attacks; COW curves concern only VI.B.2 restricted attacks. The stated calibration improvements are numerical/qualitative. (source-ambiguity)
  • Appendix A: Bell-diagonal errors and Eve’s information, Eqs.(A1)–(A4): Measured Bell purification and computed conditional Eve entropies (hard)
  • Appendix A: general six-state privacy cost, Eq.(A5): Six-state operational reduction with boundary-safe computed Bell Holevo cost (hard)
  • Appendix A: depolarizing six-state key fraction, Eq.(A6): Depolarizing six-state secure fraction and implicit first zero (hard)
  • Appendix A: BB84 entropy maximization and 11% threshold, Eqs.(A7)–(A9): BB84 entropy maximum and operational symmetry/extraction reduction (hard)
  • Appendix B: qualitative four-link repeater claims: The source reports ideal R_4 proportional to t^(1/4), four memories released before T_M, three Bell measurements, an approximately 95% fidelity requirement, and effective memory transmission p_M_prime≈p_M*t^(1/4). (source-ambiguity)

Selected references

  • The Security of Practical Quantum Key Distribution, arXiv:0802.4155v3, https://arxiv.org/abs/0802.4155v3
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Quantum Information·Captain: Goku

A Continuity Theorem for Stinespring's DilationResearch Paper

Motivation

We show a continuity theorem for Stinespring's dilation: two completely positive maps between arbitrary C*-algebras are close in cb-norm iff we can find corresponding dilations that are close in operator norm. The proof establishes the equivalence of the cb-norm distance and the Bures distance for completely positive maps. We briefly discuss applications to quantum information theory.

This mission is the statement-level formalization of A Continuity Theorem for Stinespring's Dilation (arXiv:0710.2495v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

13 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Continuity of Stinespring dilation, with attainment and minimal direct sum (Theorem 1, (6)–(7), direct-sum refinement, PDF p. 4). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Selected references

  • A Continuity Theorem for Stinespring's Dilation, arXiv:0710.2495v1, https://arxiv.org/abs/0710.2495v1
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Quantum Information·Captain: Goku

Squashed entanglement, k-extendibility, quantum Markov chains, and recovery mapsResearch Paper

Motivation

Squashed entanglement [Christandl and Winter, J. Math. Phys. 45(3):829-840 (2004)] is a monogamous entanglement measure, which implies that highly extendible states have small value of the squashed entanglement. Here, invoking a recent inequality for the quantum conditional mutual information [Fawzi and Renner, Commun. Math. Phys. 340(2):575-611 (2015)] greatly extended and simplified in various work since, we show the converse, that a small value of squashed entanglement implies that the state is close to a highly extendible state. As a corollary, we establish an alternative proof of the faithfulness of squashed entanglement [Brandao, Christandl and Yard, Commun. Math. Phys. 306:805-830 (2011)]. We briefly discuss the previous and subsequent history of the Fawzi-Renner bound and related conjectures, and close by advertising a potentially far-reaching generalization to universal and functorial recovery maps for the monotonicity of the relative entropy.

This mission is the statement-level formalization of Squashed entanglement, k-extendibility, quantum Markov chains, and recovery maps (arXiv:1410.4184v4). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

9 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Small squashed entanglement implies proximity to k-extendibility (Theorem 1, PDF p. 3). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Selected references

  • Squashed entanglement, k-extendibility, quantum Markov chains, and recovery maps, arXiv:1410.4184v4, https://arxiv.org/abs/1410.4184v4
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Quantum Information·Captain: Goku

Classification of NNN-(super)-extended Poincaré algebras and bilinear invariants of the spinor representation of Spin(p,q)Spin(p,q)Spin(p,q)Research Paper

Motivation

We classify extended Poincaré Lie super algebras and Lie algebras of any signature (p,q), that is Lie super algebras and Z_2-graded Lie algebras g = g_0 + g_1, where g_0 = so(V) + V is the (generalized) Poincaré Lie algebra of the pseudo Euclidean vector space V = R^{p,q} of signature (p,q) and g_1 = S is the spinor so(V)-module extended to a g_0-module with kernel V. The remaining super commutators {g_1,g_1} (respectively, commutators [g_1, g_1]) are defined by an so(V)-equivariant linear mapping vee^2 g_1 -> V (respectively, wedge^2 g_1 -> V). Denote by P^+(n,s) (respectively, P^-(n,s)) the vector space of all such Lie super algebras (respectively, Lie algebras), where n = p + q = dim V and s = p - q is the signature. The description of P^+-(n,s) reduces to the construction of all so(V)-invariant bilinear forms on S and to the calculation of three Z_2-valued invariants for some of them. This calculation is based on a simple explicit model of an irreducible Clifford module S for the Clifford algebra Cl_{p,q} of arbitrary signature (p,q). As a result of the classification, we obtain the numbers L^+-(n,s) = \dim P^+-(n,s) of independent Lie super algebras and algebras, which take values 0,1,2,3,4 or 6. Due to Bott periodicity, L^+-(n,s) may be considered as periodic functions with period 8 in each argument. They are invariant under the group Gamma generated by the four reflections with respect to the axes n=-2, n=2, s-1 = -2 and s-1 = 2. Moreover, the reflection (n,s) -> (-n,s) with respect to the axis s=0 interchanges L^+ and L^- : L^+(-n,s) = L^-(n,s).

This mission is the statement-level formalization of Classification of NNN-(super)-extended Poincaré algebras and bilinear invariants of the spinor representation of Spin(p,q)Spin(p,q)Spin(p,q) (arXiv:math/9511215v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

21 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Paper result: real extension dimensions, periodicity and reflection supersymmetry (Paper result: real extension dimensions, periodicity and reflection supersymmetry, PDF p. 1). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

53 results of the paper are not stated yet, because the library lacks an interface they need:

  • Proposition 1.1: Epsilon-extension isomorphism classes and pair equivalence (hard)
  • Proposition 1.2: Orthogonal and symplectic tensor amplifications with internal group actions (hard)
  • Lemma 1.3: Equivariant symmetric/exterior multiplicity decomposition (hard)
  • Theorem 1.4: All six canonical B/J/M contractions (source-ambiguity)
  • Lemma 1.11: Restriction of the standard real/complex/quaternionic matrix module to a unital split subalgebra (hard)
  • Proposition 2.1: Graded Clifford tensor MODULE action and its two parity subspaces (hard)
  • Corollary 2.2: General real tensor irreducibility and even-reducibility equivalence (source-ambiguity)
  • Proposition 2.3: Tensor forms/endomorphisms on the constructed graded module (hard)
  • Proposition 2.4: Split-factor tensor representation and even restriction (hard)
  • Proposition 3.1: Exterior creation/annihilation representation with corrected split normalization (hard)
  • Proposition 3.2: Trace-shifted exterior gl(U) action and three-step Lie grading (hard)
  • Lemma 3.3: Even/odd exterior spinor submodules (hard)
  • Proposition 3.4: Top-volume exterior form f, f_E, and the actual Schur basis (hard)
  • Theorem 3.5: The actual split f/f_E embedding pair and its complete image-location table (hard)
  • Proposition 3.6: Normalized compatible split form/endomorphism selection and tensor signs (hard)
  • Theorem 3.8: Complexification of the actual split f/f_E embeddings with the dual codomain (hard)
  • Proposition 3.9: Odd split Clifford representation on the SAME exterior carrier (hard)
  • Proposition 3.11: The actual split-odd f_E and j_(rho_tilde)(f_E) canonical generators (hard)
  • Corollary 3.12: The complex extension of the actual split-odd f_E and its Clifford embedding (hard)
  • Proposition 4.1: Explicit positive even spinor model in all four m residues (hard)
  • Lemma 4.3: Canonical exterior/Clifford identification with ordinary contraction (hard)
  • Corollary 4.4: Exterior scalar product transported to the explicit positive even model (hard)
  • Lemma 4.5: Positive complexified carrier, its real-form conjugation, and Re of the bilinear form (hard)
  • Proposition 4.6: Positive model operators alpha and L_omega alpha, with h and h_A bases (hard)
  • Proposition 4.7: Positive eight-operator model basis and both invariant tables (hard)
  • Theorem 4.8: The fixed positive-even h_A embeddings and every Table 4 image block (hard)
  • Proposition 4.9: Positive odd model and its residue-zero complexification (hard)
  • Lemma 4.10: Specified positive odd scalar product and real-form complexification (hard)
  • Proposition 4.11: Positive odd I,J,K model operators and associated bilinear basis (hard)
  • Theorem 4.12: The fixed positive-odd h_A embeddings and every Table 5 image block (hard)
  • Proposition 5.2: Explicit negative even model with distinct real and complex carriers (hard)
  • Lemma 5.3: Parity-degree transport of the exterior scalar product to Cl_(0,m) (hard)
  • Lemma 5.4: Negative-real-form conjugation and complex-bilinear scalar extension (hard)
  • Proposition 5.5: Negative model alpha, L_omega alpha, and the h/h_A bases (hard)
  • Proposition 5.6: Negative eight-operator basis and both sign tables (hard)
  • Theorem 5.7: The fixed negative-even h_A embeddings and every Table 6 image block (hard)
  • Proposition 5.8: Negative odd model, residue-one complexification, and Jhat-fixed halves (hard)
  • Lemma 5.9: Specified negative odd scalar product and conjugation branch (hard)
  • Proposition 5.10: Negative odd Jhat=L_omega alpha c, Khat, and Table 7 (hard)
  • Theorem 5.11: The fixed negative-odd h_A embeddings and every Table 8 image block (hard)
  • Theorem 6.1: Explicit normalized split-factor maps phi and psi on the chosen bases (hard)
  • Corollary 6.2: Constructed (8,0) and (0,8) form/algebra periodicity maps (hard)
  • Corollary 6.3: Canonical h and explicit admissible j_rho(h_A) generators (hard)
  • Introduction: the two Lorentz spinor brackets: Real C^2 Lorentz action and unique vector submodules in both squares (hard)
  • Introduction: bracket parametrization and automatic Jacobi identities: Signed extension structures on a fixed arbitrary real so(V)-module (hard)
  • Example 1: multiplicity and internal symmetry after amplification: Multiplicity-counted tensor amplifications with full internal groups (hard)
  • Section 1.2: criterion for charge extension preserving internal symmetry: Charged signed extension with integrated connected internal symmetry (hard)
  • Example 2: central charges from a Lie extension: Both explicit central-charge tensor brackets from an ordinary extension (hard)
  • Example 3: central charges from a super extension: Both explicit central-charge tensor brackets from a super extension (hard)
  • Section 1.3: reduction to one or two spinor summands: All Table 2/3 square decompositions including mixed blocks (hard)
  • Remark 3: admissibility independent of the reference admissible form: Reference-independent admissibility for EVERY admissible beta (source-ambiguity)
  • Section 6: invariants of the constructed embeddings: Canonical h and its concrete h_A Clifford embeddings (hard)
  • Section 6: dimensions count independent bracket structures: Actual vector space of signed Lie/super-Lie bracket structures (hard)

Selected references

  • Classification of NNN-(super)-extended Poincaré algebras and bilinear invariants of the spinor representation of Spin(p,q)Spin(p,q)Spin(p,q), arXiv:math/9511215v1, https://arxiv.org/abs/math/9511215v1
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Duality and Rational Modules in Hopf Algebras over Commutative RingsResearch Paper

Motivation

Let AAA be an algebra over a commutative ring RRR. If RRR is noetherian and A∘A^\circA∘ is pure in RAR^ARA, then the categories of rational left AAA-modules and right A∘A^\circA∘-comodules are isomorphic. In the Hopf algebra case, we can also strengthen the Blattner-Montgomery duality theorem. Finally, we give sufficient conditions to get the purity of A∘A^\circA∘ in RAR^ARA.

This mission is the statement-level formalization of Duality and Rational Modules in Hopf Algebras over Commutative Rings (arXiv:math/0011207v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

18 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Proposition 2.1 (Proposition 2.1, PDF p. 4). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

11 results of the paper are not stated yet, because the library lacks an interface they need:

  • Abstract: rational left modules and finite-dual right comodules: Full arbitrary-dimensional rational-module and right-comodule categories with the canonical inverse functors (hard)
  • Theorem 2.11: Rational-part endofunctor, left-exact preradical, inverse comodule functors, and sigma[A C] subgeneration (hard)
  • Proposition 2.15: Canonical finite-dual bialgebra/Hopf upgrades, contravariant morphisms, and pure coalgebra subobjects (hard)
  • Theorem 2.17: Both canonical categorical isomorphisms, both sigma identifications, and the full restriction/Rat commutative diagram (hard)
  • Lemma 3.1: Constructed Hopf actions, both smash-product algebras, lambda and opposite-algebra rho (hard)
  • Theorem 3.2: Right-comodule algebra, induced H-action, iterated smash algebra, RL condition, and algebra duality isomorphism (hard)
  • Remark 3.4: group-algebra duality application: Rationality/local-finiteness of the arbitrary group action, needed for the printed application of Theorem 3.2 (source-ambiguity)
  • Corollary 4.3: Canonical finite-dual coalgebra with all conditional bialgebra/Hopf upgrades and rational-pairing compatibility (hard)
  • Example 4.7: strongly graded and crossed-product algebras: Internal strong finite-group gradings and general crossed, twisted, ordinary, and skew group algebras over noncommutative coefficients (hard)
  • §4.2: polynomial algebras and their finite duals: Two distinct canonical polynomial coalgebra structures and their finite-dual bialgebra/Hopf upgrades, plus coefficient-algebra closure (hard)
  • Theorem 4.14: Multivariate central Laurent algebra closure and the canonical multiplicative-group Hopf structure on its finite dual (hard)

Selected references

  • Duality and Rational Modules in Hopf Algebras over Commutative Rings, arXiv:math/0011207v1, https://arxiv.org/abs/math/0011207v1
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Higher-Dimensional Algebra V: 2-GroupsResearch Paper

Motivation

A 2-group is a "categorified" version of a group, in which the underlying set G has been replaced by a category and the multiplication map has been replaced by a functor. Various versions of this notion have already been explored; our goal here is to provide a detailed introduction to two, which we call "weak" and "coherent" 2-groups. A weak 2-group is a weak monoidal category in which every morphism has an inverse and every object x has a "weak inverse": an object y such that x tensor y and y tensor x are isomorphic to 1. A coherent 2-group is a weak 2-group in which every object x is equipped with a specified weak inverse x* and isomorphisms i_x: 1 -> x tensor x* and e_x: x* tensor x -> 1 forming an adjunction. We describe 2-categories of weak and coherent 2-groups and an "improvement" 2-functor that turns weak 2-groups into coherent ones, and prove that this 2-functor is a 2-equivalence of 2-categories. We internalize the concept of coherent 2-group, which gives a quick way to define Lie 2-groups. We give a tour of examples, including the "fundamental 2-group" of a space and various Lie 2-groups. We also explain how coherent 2-groups can be classified in terms of 3rd cohomology classes in group cohomology. Finally, using this classification, we construct for any connected and simply-connected compact simple Lie group G a family of 2-groups G_hbar (for integral values of hbar) having G as its group of objects and U(1) as the group of automorphisms of its identity object. These 2-groups are built using Chern-Simons theory, and are closely related to the Lie 2-algebras g_hbar (for real hbar) described in a companion paper.

This mission is the statement-level formalization of Higher-Dimensional Algebra V: 2-Groups (arXiv:math/0307200v3). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

8 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Strong monoidal functors preserve weak inverses (Proposition 3: strong monoidal functors preserve weak inverses, PDF p. 9). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

37 results of the paper are not stated yet, because the library lacks an interface they need:

  • Abstract; Theorem 17: improvement and forgetting are a 2-equivalence: Universe-correct W2G and C2G, strict improvement/forgetting 2-functors, and a 2-natural isomorphism (hard)
  • Proposition 11: free coherent 2-groups: The strict-preservation category c2g and its object-set forgetful functor (hard)
  • Theorem 12: coherence of free coherent 2-groups: A syntactic free coherent 2-group and substitution functor on c2g (hard)
  • Corollary 16: improvement extends to a 2-functor: The strict 2-category structures and actual Imp 2-functor (hard)
  • Proposition 20: internal coherent 2-groups in Cat: Internal coherent 2-group in Cat with natural covariant inverse functor (hard)
  • Proposition 32: internal strict 2-groups and crossed modules: Internal groups, kernels, semidirect products and internal category objects for arbitrary K (hard)
  • Proposition 39: every coherent 2-group equivalent to a special one: A source-corrected, explicitly scoped replacement for the printed assertion (source-ambiguity)
  • Lemma 40: transport coherent structure along tensor comparison: Dependent transport of full monoidal/coherent data with specified identity comparisons (hard)
  • Proposition 42: normalize homomorphisms of special 2-groups: Special coherent objects, normalized strong monoidal functors and monoidal natural isomorphisms (hard)
  • Theorem 43: cohomological description of objects, homomorphisms and 2-homomorphisms: A source-corrected, explicitly scoped replacement for the printed assertion (source-ambiguity)
  • Corollary 44: classification up to equivalence by H3 data: Intrinsic associator cohomology invariant and quotient of quadruples by compatible group isomorphisms (hard)
  • Proposition 45: strictification without preserving skeletalness: Fully strict 2-group structure and strong monoidal equivalence (hard)
  • Theorem 55: integer Chern–Simons family: A source-corrected, explicitly scoped replacement for the printed assertion (source-ambiguity)
  • Proposition 58: classification of special internal 2-groups: A source-corrected, explicitly scoped replacement for the printed assertion (source-ambiguity)
  • Theorem 59: special topological 2-groups with connected Lie data have vanishing associator class: Special topological 2-groups, global continuous H3 and continuous special equivalence (hard)
  • Corollary 60: no ordinary topology on nonzero Chern–Simons examples: Chern–Simons integral class injection and isomorphism to the topological family presentation (hard)
  • Example 33: Strict automorphism 2-group: Strict automorphism monoidal groupoid of an arbitrary strict 2-category (hard)
  • Example 34: Weak automorphism 2-group: Weak automorphism monoidal groupoid of an arbitrary bicategory (hard)
  • Example 35: Autoequivalence 2-group: Autoequivalence groupoid with nonadjoint equivalence data and compatible pairs of 2-isomorphisms (hard)
  • Example 36: Adjoint autoequivalence 2-group: Adjoint autoequivalence groupoid with paired compatible 2-isomorphisms (hard)
  • Example 47: Skeletal strict Lie 2-groups from smooth actions: Smooth crossed-module/internal Lie-category construction and converse for every skeletal strict Lie 2-group (hard)
  • Example 48: Tangent 2-group: Tangent Lie group, adjoint semidirect product identification and tangent groupoid (hard)
  • Example 49: Cotangent 2-group: Coadjoint semidirect product Lie groupoid and fixed cotangent trivialization (hard)
  • Example 50: Representations and Poincare 2-groups: Representation Lie 2-group and its defining Lorentz/Poincare specialization (hard)
  • Example 51: Strict Lie automorphism 2-group: A source-corrected, explicitly scoped replacement for the printed assertion (source-ambiguity)
  • Example 52: SU(2) and quaternionic automorphism examples: A source-corrected, explicitly scoped replacement for the printed assertion (source-ambiguity)
  • Example 53: Surjective crossed modules are precisely central extensions: Unique smooth descended conjugation action for a surjective smooth homomorphism (hard)
  • Example 54: Heisenberg 2-group: Heisenberg Lie group with coefficient-one multiplication and resulting Lie 2-group (hard)
  • Section 7: internal categories form a strict 2-category with products: KCat with internal functors/transformations, strict 2-category laws and finite products (hard)
  • Section 8.1: bitorsors are equivalent to the strict automorphism 2-group: Balanced-product monoidal groupoid of bitorsors and monoidal equivalence to Auts(G) (hard)
  • Section 8.2: fundamental coherent 2-group of a pointed space: Actual loops, relative-boundary bigon quotient and reverse-path adjunction (hard)
  • Section 8.2: realize an autoequivalence 2-group topologically: A source-corrected comparison between an adjoint-equivalence core and its fundamental 2-group, explicitly distinguishing Auteq from Autad (source-ambiguity)
  • Section 8.2: proposed biequivalence with pointed connected homotopy 2-types: A source-corrected, explicitly scoped replacement for the printed assertion (source-ambiguity)
  • Section 8.3: vanishing H3 class characterizes skeletal strictification: Intrinsic H3 class and simultaneous skeletal/strict representative equivalence (hard)
  • Section 8.4: strict Lie 2-groups and Lie crossed modules: Two categories of smooth internal groupoids/crossed modules with derivation 2-morphisms (hard)
  • Section 8.4: tangent groupoid is a product-preserving functor: Product-preserving Diff to DiffCat tangent-groupoid functor (hard)
  • Section 8.5 proof: connected compact Lie continuous cohomology vanishes in degree at least three: Global normalized continuous cochain complex for arbitrary connected abelian Lie coefficients (hard)

Selected references

  • Higher-Dimensional Algebra V: 2-Groups, arXiv:math/0307200v3, https://arxiv.org/abs/math/0307200v3
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Markov triplets on CCR-algebrasResearch Paper

Motivation

The paper contains a detailed computation about the algebra of canonical commutation relation, the representation of the Weyl unitaries, the quasi-free states and their von Neumann entropy. The Markov triplet is defined by constant entropy increase. The Markov property of a quasi-free state is described by the representing block matrix. The proof is based on results on the statistical sufficiency in the quantum case. The relation to classical Gaussian Markov triplets is also described.

This mission is the statement-level formalization of Markov triplets on CCR-algebras (arXiv:0812.3724v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

11 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Markov quasifree triplets characterized by a separating projection (Theorem 2.3 (paper headline), PDF p. 17). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

12 results of the paper are not stated yet, because the library lacks an interface they need:

  • Lemma 1.3: Completed symmetric Fock functor and its canonical tensor identification for arbitrary complex Hilbert spaces (hard)
  • Lemma 1.4: Creation, annihilation and differential second quantization on the common finite-particle symmetric-tensor domain (hard)
  • Lemma 1.5: Domain/closure convention for arbitrary bounded one-particle second-quantization products (source-ambiguity)
  • Lemma 1.6: Unbounded sectorwise Gamma and closure of its algebraic tensor product under the canonical Fock unitary (hard)
  • Example 1.1: Actual CCR/Fock normal-state restrictions and tensor product on the whole subsystem algebra (hard)
  • Theorem 1.3: Constructed multimode bosonic density, unnormalized occupation expansion, and unbounded two-point expectations (hard)
  • Theorem 1.4: Connes cocycle and zero-eigenvalue imaginary powers for nonfaithful pairs (source-ambiguity)
  • Theorem 1.5: Normal full-Fock states with finite unbounded second moments, extended entropy and uniqueness (hard)
  • Theorem 2.1: Boundary imaginary powers in the all-positive-semidefinite Markov equivalence (source-ambiguity)
  • Outer-subalgebras-independent: Product equality on the complete outer CCR subsystem algebra (hard)
  • Lemma 3.1: Actual commuting-field spectral law tied to the quasifree normal state (hard)
  • Theorem 3.1: Correct hypothesis for preservation of classical conditional independence under the allowed complex field choices (source-ambiguity)

Selected references

  • Markov triplets on CCR-algebras, arXiv:0812.3724v2, https://arxiv.org/abs/0812.3724v2
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Composing Quantum Protocols in a Classical EnvironmentResearch Paper

Motivation

We propose a general security definition for cryptographic quantum protocols that implement classical non-reactive two-party tasks. The definition is expressed in terms of simple quantum-information-theoretic conditions which must be satisfied by the protocol to be secure. The conditions are uniquely determined by the ideal functionality F defining the cryptographic task to be implemented. We then show the following composition result. If quantum protocols pi_1,...,pi_k securely implement ideal functionalities F_1,...,F_k according to our security definition, then any purely classical two-party protocol, which makes sequential calls to F_1,...,F_k, is equally secure as the protocol obtained by replacing the calls to F_1,...,F_k with the respective quantum protocols pi_1,...,pi_k. Hence, our approach yields the minimal security requirements which are strong enough for the typical use of quantum protocols as subroutines within larger classical schemes. Finally, we show that recently proposed quantum protocols for oblivious transfer and secure identification in the bounded-quantum-storage model satisfy our security definition, and thus compose in the above sense.

This mission is the statement-level formalization of Composing Quantum Protocols in a Classical Environment (arXiv:0804.1059v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

3 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Lemma 2.1: three approximate conditional-independence bounds (Lemma 2.1, PDF p. 4). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

13 results of the paper are not stated yet, because the library lacks an interface they need:

  • Paper headline / Theorem 5.1: composing quantum protocols in a classical environment: Operational two-party CPTP strategies, computed real/ideal execution, and the source-exact Definition 4.1 on the same protocol; computed sequential hybrid substitution (hard)
  • Proposition 4.2: security with classical side information and conditional quantum input: Operational two-party CPTP strategies, computed real/ideal execution, and the source-exact Definition 4.1 on the same protocol (hard)
  • Proposition 4.3: simulation for conditionally independent quantum input: Operational two-party CPTP strategies, computed real/ideal execution, and the source-exact Definition 4.1 on the same protocol (hard)
  • Corollary 5.2: security of a hybrid implementation after substitution: Admissibility of the hybrid simulators in the adversary classes required by hybrid security (source-ambiguity)
  • Proposition 6.2: identification security implies ideal functionality security: Operational two-party CPTP strategies, computed real/ideal execution, and the source-exact Definition 4.1 on the same protocol (hard)
  • Proposition 7.2: sender-randomized 1-2 OT security implies ideal functionality security: Operational two-party CPTP strategies, computed real/ideal execution, and the source-exact Definition 4.1 on the same protocol (hard)
  • Unnumbered §7: bootstrapping randomized-OT correctness from the older definition: A quantitative error conversion for the older randomized-OT correctness definition (source-ambiguity)
  • Proposition B.2: regular 1-2 OT security implies ideal functionality security: Operational two-party CPTP strategies, computed real/ideal execution, and the source-exact Definition 4.1 on the same protocol (hard)
  • Proposition B.4: fully randomized 1-2 OT security implies ideal functionality security: A source-justified sharp Markov estimate consistent with the printed 4ε headline (source-ambiguity)
  • Proposition B.6: randomized Rabin OT security implies ideal functionality security: Operational two-party CPTP strategies, computed real/ideal execution, and the source-exact Definition 4.1 on the same protocol (hard)
  • Proposition C.2: identification without unfairness: A source-justified ε Markov estimate or an independently justified correction of the headline constant (source-ambiguity)
  • Unnumbered introduction: composability of the cited bounded-storage protocols: Concrete cited protocol implementations, their memory bounds, and a source-exact security/correctness bridge (hard)
  • Unnumbered Appendix C: the cited identification protocol also satisfies the stronger definition: The concrete cited Q-ID execution and a complete match of its extractor/security experiment to Definition C.1 (hard)

Selected references

  • Composing Quantum Protocols in a Classical Environment, arXiv:0804.1059v2, https://arxiv.org/abs/0804.1059v2
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Bernstein functions and rates in mean ergodic theorems for operator semigroupsResearch Paper

Motivation

We present a functional calculus approach to the study of rates of decay in mean ergodic theorems for bounded strongly continuous operator semigroups. A central role is played by operators of the form g(A)g(A)g(A), where −A-A−A is the generator of the semigroup and ggg is a Bernstein function. In addition, we obtain some new results on Bernstein functions that are of independent interest.

This mission is the statement-level formalization of Bernstein functions and rates in mean ergodic theorems for operator semigroups (arXiv:1112.0286v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

30 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Theorem 3.4. (Theorem 3.4., PDF p. 16). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

5 results of the paper are not stated yet, because the library lacks an interface they need:

  • §2.1, unnumbered Laplace algebra and convolution identities: Full complex Radon-measure convolution, exponential twisting and Banach-algebra transport (hard)
  • §5, unnumbered logarithm resolvent representation: Concrete sectorial logarithm and its equality with the same-semigroup regularized HP logarithm (hard)
  • Theorem 2.12.: Missing exclusion of nonzero constant complete Bernstein functions (source-ambiguity)
  • Theorem 5.2.: False little-o clause and unspecified zeros in the denominator of part (a) (source-ambiguity)
  • Remark 5.3.: Reciprocal quotient undefined for the allowed constant complete Bernstein functions (source-ambiguity)

Selected references

  • Bernstein functions and rates in mean ergodic theorems for operator semigroups, arXiv:1112.0286v1, https://arxiv.org/abs/1112.0286v1
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Reflection Positive Stochastic Processes Indexed by Lie GroupsResearch Paper

Motivation

Reflection positivity originates from one of the Osterwalder-Schrader axioms for constructive quantum field theory. It serves as a bridge between euclidean and relativistic quantum field theory. In mathematics, more specifically, in representation theory, it is related to the Cartan duality of symmetric Lie groups (Lie groups with an involution) and results in a transformation of a unitary representation of a symmetric Lie group to a unitary representation of its Cartan dual. In this article we continue our investigation of representation theoretic aspects of reflection positivity by discussing reflection positive Markov processes indexed by Lie groups, measures on path spaces, and invariant gaussian measures in spaces of distribution vectors. This provides new constructions of reflection positive unitary representations.

This mission is the statement-level formalization of Reflection Positive Stochastic Processes Indexed by Lie Groups (arXiv:1510.07445v3). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

8 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Consistent convolution path laws and their sigma-finite extension (Lemma 4.8, PDF p. 30). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

28 results of the paper are not stated yet, because the library lacks an interface they need:

  • Lemma 2.3: OS quotient of a semidefinite Hilbert form (hard)
  • Proposition 2.9: OS-induced semigroup and canonical Gamma (hard)
  • Lemma 2.10: symmetric-semigroup reflection representation and Markov projection identity (hard)
  • Proposition 3.3: measure-algebra reflection model and associated OS quotient (hard)
  • Proposition 3.7: abstract positive semigroup structure and probability realization (hard)
  • Lemma 3.16: quantized initial multiplication algebra and extended ordered moments (hard)
  • Theorem 3.18: positive semigroup structure and associated measure-algebra probability model (hard)
  • Lemma 3.21: consistent past/future cylinder prescription under the printed hypotheses (source-ambiguity)
  • Theorem 3.22: sigma-finite standard positive semigroup realization and measure-algebra uniqueness (hard)
  • Theorem 3.27: associated quantized initial algebra and canonical vacuum (hard)
  • Proposition 4.2: joined pinned forward/backward increment law (hard)
  • Theorem 4.9: conditional L2 Markov path model and generated unitary dilation (hard)
  • Lemma 5.5: real Gaussian second quantization and standard positive semigroup (hard)
  • Proposition 5.6: Gaussian functor applied to a real reflection representation (hard)
  • Theorem 5.7: nuclear-space covariance RKHS and its continuous-dual Gaussian measure (hard)
  • Proposition 5.10: Lie-group test-function LF space, distribution RKHS and distribution vectors (hard)
  • Lemma 5.12: smooth-vector Frechet topology and cyclic distribution vector (hard)
  • Theorem 5.13: orthogonal distribution covariance sums and component intertwiners (hard)
  • Corollary 5.14: Gaussian laws of positive distribution vectors in H_D-minus-infinity (hard)
  • Theorem 5.17: locally convex nuclearity, graph-Frechet smooth domain, continuous real dual and Gaussian realization (hard)
  • Corollary 5.19: smooth-vector nuclearity, closed Nelson Laplacian and real-dual Gaussian realization (hard)
  • Proposition 5.20: smooth-vector locally convex nuclearity for Lie representations (hard)
  • Theorem 5.26: canonical Gaussian action, Fock decomposition and weak mixing against every rho (hard)
  • §3.2, unnumbered: covariance RKHS realization: canonical embedded scalar/operator-valued covariance RKHS (hard)
  • §3.6, unnumbered: reversible discrete Markov realization: reversible Polish Markov L2 compression and finite-state specialization (hard)
  • §3.5, unnumbered: SL2-cover semigroup triviality: specific universal SL2 cover and lifted total semigroup (hard)
  • §4, unnumbered main result: path measure factorization: canonical pinned law and skew-product decomposition (hard)
  • Example 5.15, unnumbered: abelian Gaussian equivalence: tempered covariance Fourier transforms and distribution Gaussian comparison (hard)

Selected references

  • Reflection Positive Stochastic Processes Indexed by Lie Groups, arXiv:1510.07445v3, https://arxiv.org/abs/1510.07445v3
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Smoothing operators and C∗C^*C∗-algebras for infinite dimensional Lie groupsResearch Paper

Motivation

A host algebra of a (possibly infinite dimensional) Lie group GGG is a C∗C^*C∗-algebra whose representations are in one-to-one correspondence with certain continuous unitary representations π ⁣:G→\U(\cH)π\colon G \to \U(\cH)π:G→\U(\cH). In this paper we present a new approach to host algebras for infinite dimensional Lie groups which is based on smoothing operators, i.e., operators whose range is contained in the space \cH∞\cH^\infty\cH∞ of smooth vectors. Our first major result is a characterization of smoothing operators AAA that in particular implies smoothness of the maps πA ⁣:G→B(\cH),g↦π(g)Aπ^A \colon G \to B(\cH), g \mapsto π(g)AπA:G→B(\cH),g↦π(g)A. The concept of a smoothing operator is particularly powerful for representations (π,\cH)(π,\cH)(π,\cH) which are semibounded, i.e., there exists an element x0∈\gx_0 \in\gx0​∈\g for which all operators i\ddπ(x)i\ddπ(x)i\ddπ(x), x∈\gx \in \gx∈\g, from the derived representation are uniformly bounded from above in some neighborhood of x0x_0x0​. Our second main result asserts that this implies that \cH∞\cH^\infty\cH∞ coincides with the space of smooth vectors for the one-parameter group πx0(t)=π(exp⁡tx0)π_{x_0}(t) = π(\exp tx_0)πx0​​(t)=π(exptx0​). We then show that natural types of smoothing operators can be used to obtain host algebras and that, for every metrizable Lie group, the class of semibounded representations can be covered completely by host algebras. In particular, it permits direct integral decompositions.

This mission is the statement-level formalization of Smoothing operators and C∗C^*C∗-algebras for infinite dimensional Lie groups (arXiv:1505.02659v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

9 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Smoothing operators for Frechet--Lie groups (Abstract, first main result: smoothing versus norm-smooth orbit (Fréchet specialization), PDF p. 1). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

28 results of the paper are not stated yet, because the library lacks an interface they need:

  • Abstract: direct integral consequence (unquantified): Measurable-field and decomposition hypotheses (source-ambiguity)
  • Example 1.1: non-Fréchet subgroup counterexample: Lp multiplication representation with inherited subgroup topology (hard)
  • Example 2.1: integrated, one-parameter, and heat smoothing: Integrated representations, distributional derivatives, unbounded spectral multipliers and Nelson Laplacian (hard)
  • Example 2.2: smoothing by holomorphic extension: Locally convex holomorphic complex-group and open-semigroup interface (hard)
  • Proposition 2.1: Haar-integrated test-function representation along a smooth homomorphism (hard)
  • Corollary 2.1: Integrated one-parameter test-function operators (hard)
  • Proposition 2.2: Unbounded selfadjoint spectral exponential and analytic-vector convergence domain (hard)
  • Example 2.3: compact homogeneous manifolds: Diffeomorphism-group Lie charts and half-density L2 action (hard)
  • Lemma 3.1: Hilbert-scale commutator estimate: Canonical Hilbert scales and their constructed commutator (hard)
  • Definition 3.1: momentum and semiboundedness properties: Actual spectral support, momentum set and adjoint tangent action (hard)
  • Theorem 3.1: Zellner’s Smooth Vector Theorem: Spectral semiboundedness and quantitative Hilbert-scale operator N (hard)
  • Remark 3.1: Minkowski seminorm and weaker topology: Momentum sublevel gauges and their generated weaker topology (hard)
  • Proposition 3.2: Countable graph topology on a semibounded smooth-vector space (hard)
  • Lemma 4.1: Canonical double-centralizer multiplier action and representation extension (hard)
  • Remark 4.2: host injectivity criterion: Host H2 injectivity through canonical multiplier extensions (hard)
  • Theorem 4.1: Subgroup Host Algebra Theorem: Subgroup-integrated generated host algebra and representation correspondence (hard)
  • Lemma 4.2: Transport of unbounded selfadjoint spectral exponentials by multipliers (hard)
  • Theorem 4.2: Single-generator heat host algebra with transported spectral bound (hard)
  • Theorem 4.3: Semibounded exponential-family host algebra and momentum transport (hard)
  • Corollary 4.1: host algebra for support bounds: Universal GNS direct sum and support-bounded host correspondence (hard)
  • Lemma 4.3: Unbounded complex spectral semigroup on the closed upper half-plane (hard)
  • Proposition 4.1: independence of x0: Constructed single-generator and full-family host algebras (hard)
  • Remark 5.1: compactness on generators: Irreducible nondegenerate C*-representations of the generated algebra (hard)
  • Example 5.1: subgroup-host liminality criterion: Subgroup host liminality via every irreducible representation (hard)
  • Example 5.2: semibounded-host liminality criterion: Semibounded host liminality via all irreducible semibounded G-representations (hard)
  • Section 6.1: smoothing spectral projections: Compact-interval spectral projections and Grassmannian orbit (hard)
  • Section 6.2: unique Fréchet topology and semibounded Fréchet smoothness: Unique Frechet topologies together with the semibounded graph topology and smooth action (hard)
  • Proposition 6.1: extension along dense Lie algebra inclusions: Actual differential of a dense Lie inclusion and spectral-support extension (hard)

Selected references

  • Smoothing operators and C∗C^*C∗-algebras for infinite dimensional Lie groups, arXiv:1505.02659v2, https://arxiv.org/abs/1505.02659v2
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Quantum Information·Captain: Goku

Reverse Coherent InformationResearch Paper

Motivation

In this letter we define a family of entanglement distribution protocols assisted by feedback classical communication that gives an operational interpretation to reverse coherent information, i.e., the symmetric counterpart of the well known coherent information. This lead to the definition of a new entanglement distribution capacity that exceeds the unassisted capacity for some interesting channels.

This mission is the statement-level formalization of Reverse Coherent Information (arXiv:0808.0210v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

20 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Operational lower bound and single-letter reverse coherent information (pp.1–3, Eqs.(4)–(7), PDF p. 3). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

4 results of the paper are not stated yet, because the library lacks an interface they need:

  • strict comparison above the antidegradability paragraph: GAD strict comparison on an unspecified parameter/clipping regime (source-ambiguity)
  • nonnegativity assertion after GAD antidegradability: A consistent nonnegative reverse-capacity convention (source-ambiguity)
  • Eqs.(29)–(33): Correct general GAD joint spectrum with certified nested coefficients (source-ambiguity)
  • Extremum Search, Eqs.(36)–(39) and Fig.8: A specified domain and certified universal stationary-point classification (source-ambiguity)

Selected references

  • Reverse Coherent Information, arXiv:0808.0210v2, https://arxiv.org/abs/0808.0210v2
27 thms2 active usersReviewed
🏆Completed
Quantum Information·Captain: Goku

Central Extensions of Smooth 2-Groups and a Finite-Dimensional String 2-GroupResearch Paper

Motivation

We provide a model of the String group as a central extension of finite-dimensional 2-groups in the bicategory of Lie groupoids, left-principal bibundles, and bibundle maps. This bicategory is a geometric incarnation of the bicategory of smooth stacks and generalizes the more naïve 2-category of Lie groupoids, smooth functors, and smooth natural transformations. In particular this notion of smooth 2-group subsumes the notion of Lie 2-group introduced by Baez-Lauda. More precisely we classify a large family of these central extensions in terms of the topological group cohomology introduced by G. Segal, and our String 2-group is a special case of such extensions. There is a nerve construction which can be applied to these 2-groups to obtain a simplicial manifold, allowing comparison with with the model of A. Henriques. The geometric realization is an A∞A_\inftyA∞​-space, and in the case of our model, has the correct homotopy type of String(n). Unlike all previous models our construction takes place entirely within the framework of finite dimensional manifolds and Lie groupoids. Moreover within this context our model is characterized by a strong uniqueness result. It is a unique central extension of Spin(n).

This mission is the statement-level formalization of Central Extensions of Smooth 2-Groups and a Finite-Dimensional String 2-Group (arXiv:0911.2483v3). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

3 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Lemma 51: double inverse is naturally identity (Lemma 51, PDF p. 20). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

36 results of the paper are not stated yet, because the library lacks an interface they need:

  • Theorem 1: classification of central extensions: Smooth central-extension bicategory, smooth Segal-Mitchison cohomology and symmetric monoidal biequivalence (hard)
  • Theorem 2: finite-dimensional String model and coherent uniqueness: Spin(n), fixed-class smooth extension bicategory, and String realization (hard)
  • Lemma 9: Cech groupoid equivalence over X: Smooth internal Cech groupoids, slice functors and natural isomorphisms (hard)
  • Proposition 23: bundlization criterion [Ler08]: Left-principal smooth bibundle, bundlization and bibundle isomorphism (hard)
  • Theorem 26: stacks, bibundles and localization (Pronk [Pro96]): Bibun, presentable smooth stacks and bicategorical localization at essential equivalences (hard)
  • Lemma 29: four action-base-change transversality statements: Transversality of target anchors and four smooth action-base-change domains (hard)
  • Lemma 30: transverse contracted product is a manifold: Reversed right-principal bibundle and smooth contracted coequalizer (hard)
  • Proposition 31: transverse weak pullbacks in Bibun: Bibun pullback cone and universal equivalence of cone categories (hard)
  • Theorem 57: three equivalent 2-group conditions: Weak pushout F of monoidal categories, map s and s-locality (hard)
  • Corollary 59: cocompleteness and monadic reflection: Bicategory of weak 2-groups, weak colimits, reflection and two-monadicity (hard)
  • Corollary 60: free 2-group adjunction is monadic: Forgetful pseudofunctor from weak 2-groups to groupoids and free weak adjunction (hard)
  • Theorem 61: 2-groups in localized groupoid presheaves: Reflective groupoid-presheaf bicategory, monoidal objects and evaluation adjoints (hard)
  • Lemma 76: kernel square of an extension: Principal smooth two-group extension and homotopy kernel cone (hard)
  • Proposition 79: initial kernel square: Kernel-square bicategory KS(f) with fixed-edge morphisms (hard)
  • Lemma 80: extension descent is a homotopy colimit: Augmented weak Cech simplicial two-group and bicolimit cone (hard)
  • Corollary 81: monadic bar resolution: Monadic weak adjunction, augmented comonadic bar and bicolimit (hard)
  • Lemma 82: induced conjugation action on an abelian kernel: Automorphism two-group and conjugation-compatible descent category (hard)
  • Lemma 84: skeletal discrete extension classification: Skeletal weak two-group Gamma(G,A,rho,alpha) and extension equivalence (hard)
  • Lemma 88: relative universal bundle: Universal groupoid bundle realization, contracted space and topological section space (hard)
  • Corollary 89: homotopy-functorial bibundle realization: Section-space family of realized bibundle maps and composition (hard)
  • Corollary 91: Morita invariance of realization: Morita bibundle equivalence and nerve realization homotopy equivalence (hard)
  • Theorem 94: natural A-infinity realization: Section-space nonsymmetric A-infinity operad and its algebra (hard)
  • Corollary 97: circle and integral coefficients: Smooth Segal-Mitchison cochain complex, coefficient connecting maps and BG comparison (hard)
  • Lemma 98: splitting a cochain bicategory: Strict symmetric monoidal cochain bicategory and its coherent splitting (hard)
  • Theorem 99: natural cocycle-level extension classification: Normalized smooth cocycle bicategory and cocycle-to-extension pseudofunctor (hard)
  • Theorem 100: generator extension models String(n): Smooth Spin(n), generator classification and realized String projection (hard)
  • Remark 58: groupoid characterization and F equivalent to Z: Isomorphism-class monoid of a monoidal groupoid and weak pushout F (hard)
  • Example 62: free 2-groups on all smooth stacks: All smooth stacks, stackification localization and free two-group adjunction (hard)
  • Unnumbered: abelian extension square is also a pushout: Abelian smooth two-group extension and bicategorical pushout cone (hard)
  • Unnumbered: symmetric monoidal bicategory of central extensions: Central-extension bicategory with pullback/pushforward and Baer sum (hard)
  • Unnumbered: functorial group-like H-space realization: Smooth two-group realization, group-like H-space and homotopy functor (hard)
  • Remark 95: homomorphisms realize to A-infinity morphisms: Compatible section-operad structures and A-infinity morphism (hard)
  • Unnumbered §4.3: cocycle edge class and realized extension: Topological Dold-Kan double delooping, edge map and realized pullback (hard)
  • Remark 101: opposite generators and coefficient inversion: Coefficient-inversion comparison of opposite-generator extensions (hard)
  • Unnumbered §4.4: extensions with nontrivial module action: Twisted smooth Segal-Mitchison cocycle extension with its induced action (hard)
  • Unnumbered §4.4: announced general cohomological classification: Bicategorical H2(G;A), connecting maps and degree-shift comparison (source-ambiguity)

Selected references

  • Central Extensions of Smooth 2-Groups and a Finite-Dimensional String 2-Group, arXiv:0911.2483v3, https://arxiv.org/abs/0911.2483v3
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Quantum Information·Captain: Goku

On the freeness of the cyclotomic BMW algebras: admissibility and an isomorphism with the cyclotomic Kauffman tangle algebrasResearch Paper

Motivation

The cyclotomic Birman-Murakami-Wenzl (BMW) algebras B_n^k, introduced by R. Häring-Oldenburg, are a generalisation of the BMW algebras associated with the cyclotomic Hecke algebras of type G(k,1,n) (aka Ariki-Koike algebras) and type B knot theory. In this paper, we prove the algebra is free and of rank k^n (2n-1)!! over ground rings with parameters satisfying so-called "admissibility conditions". These conditions are necessary in order for these results to hold and originally arise from the representation theory of B_2^k, which is analysed by the authors in a previous paper. Furthermore, we obtain a geometric realisation of B_n^k as a cyclotomic version of the Kauffman tangle algebra, in terms of affine n-tangles in the solid torus, and produce explicit bases that may be described both algebraically and diagrammatically. The admissibility conditions are the most general offered in the literature for which these results hold; they are necessary and sufficient for all results for general n.

This mission is the statement-level formalization of On the freeness of the cyclotomic BMW algebras: admissibility and an isomorphism with the cyclotomic Kauffman tangle algebras (arXiv:0911.5284v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

11 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Proposition 2.2 (Proposition 2.2, PDF p. 6). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

16 results of the paper are not stated yet, because the library lacks an interface they need:

  • Abstract: freeness, explicit bases and canonical geometric realization: geometric basis and canonical realization (hard)
  • Theorem 3.2: arbitrary Hecke bases, bijective lifts and canonical smaller-level maps (hard)
  • Lemma 3.8: reversal anti-involution, barred chains, lifted Hecke sections and ideal filtration (hard)
  • Lemma 4.2: formal Laurent polynomial ring Omega, admissibility ideals I0,Iplus,Iminus and delta localizations (hard)
  • Proposition 4.4: specific universal admissible ring R0 and parameter evaluation maps (hard)
  • Lemma 6.1: geometric affine (2,0)-tangle quotient, Y action and cup (hard)
  • Proposition 6.2: geometric cyclotomic KT0, empty diagram inclusion and weak admissibility (hard)
  • Lemma 7.3: labelled Brauer concatenation algebra over Rc and closure trace (hard)
  • Theorem 8.1: generic admissible coefficient ring, explicit lifted word family, closure trace and canonical geometric map (hard)
  • Corollary 8.2: admissible general-ring basis family and canonical BMW-to-geometric-KT map (hard)
  • Unnumbered: general admissibility equivalences: general admissibility polynomials and the rank-k B2 module of (47) (hard)
  • Unnumbered: admissibility implies weak admissibility: integer loop extension by (57) and nonsplit admissibility predicates (hard)
  • Unnumbered: canonical diagram map and specialization: canonical geometric psi, tangle coefficient specialization and generator-preserving BMW base change (hard)
  • Unnumbered: closure traces and specialization: unnormalized geometric closure traces and their specialization maps (hard)
  • Unnumbered: Brauer specialization: canonical Brauer specialization xi, Rc, coefficient quotient maps and both traces (hard)
  • Unnumbered: injective strand inclusions: canonical generator-preserving strand homomorphisms of nonsplit admissible BMW algebras (hard)

Selected references

  • On the freeness of the cyclotomic BMW algebras: admissibility and an isomorphism with the cyclotomic Kauffman tangle algebras, arXiv:0911.5284v1, https://arxiv.org/abs/0911.5284v1
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Quantum Information·Captain: Goku

Fundamental rate-loss tradeoff for optical quantum key distributionResearch Paper

Motivation

Since 1984, various optical quantum key distribution (QKD) protocols have been proposed and examined. In all of them, the rate of secret key generation decays exponentially with distance. A natural and fundamental question is then whether there are yet-to-be discovered optical QKD protocols (without quantum repeaters) that could circumvent this rate-distance tradeoff. This paper provides a major step towards answering this question. We show that the secret-key-agreement capacity of a lossy and noisy optical channel assisted by unlimited two-way public classical communication is limited by an upper bound that is solely a function of the channel loss, regardless of how much optical power the protocol may use. Our result has major implications for understanding the secret-key-agreement capacity of optical channels---a long-standing open problem in optical quantum information theory---and strongly suggests a real need for quantum repeaters to perform QKD at high rates over long distances.

This mission is the statement-level formalization of Fundamental rate-loss tradeoff for optical quantum key distribution (arXiv:1504.06390v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

3 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Five-party pure-state subadditivity of squashed entanglement (Lemma 2: five-party pure-state subadditivity, PDF p. 4). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

12 results of the paper are not stated yet, because the library lacks an interface they need:

  • Main rate–loss bound, Eq. (1), announced in the abstract: Operational pure-loss two-way secret-key capacity over the union of finite mean-energy budgets (hard)
  • Theorem 1 / Eq. (4): channel squashed entanglement bounds P2: Operational two-way assisted private channel capacity for arbitrary finite CPTP channels (hard)
  • Unnumbered: opposite-direction channel pair bound: Adaptive paired-round private channel capacity for forward N and backward M (hard)
  • Unnumbered: two-way quantum capacity bound: Two-way quantum communication capacity and private-capacity hierarchy for channels (hard)
  • Unnumbered: excess-noise/data-processing consequence: Normal output postprocessing of the pure-loss link within operational private capacity and channel squashed entanglement (hard)
  • Supplementary Eq. (10): squashing via conditional entropies: Extended trace-class CQMI, finite-B-entropy conditional entropy, and unrestricted isometric squashing (hard)
  • Supplementary Note 2: all-input thermal maximization: All-input conditional entropies of the fixed pure-loss squashing network (hard)
  • Supplementary Eq. (11) and preceding marginal entropies: Computed three-mode thermal output and bit entropies of its four reduced states (hard)
  • Eq. (6), simplified bound and Supplementary Eq. (12): Energy-constrained operational capacity and energy-constrained channel squashed entanglement of the actual loss map (hard)
  • Unnumbered: capacity scales linearly at high loss: Operational finite-budget-union optical private capacity and its achievable reverse-coherent lower curve (hard)
  • Unnumbered: optical bidirectional specialization: Paired-round optical private capacity over two independent equal-loss links (hard)
  • Methods: finite-use rate inequality and fixed-error asymptotic consequence: Justification for substituting key dimension for full key-plus-shield dimension in the printed continuity bound (source-ambiguity)

Selected references

  • Fundamental rate-loss tradeoff for optical quantum key distribution, arXiv:1504.06390v1, https://arxiv.org/abs/1504.06390v1
7 thms2 active usersReviewed
Quantum Information·Captain: Goku

A Tight High-Order Entropic Quantum Uncertainty Relation With ApplicationsResearch Paper

Motivation

We derive a new entropic quantum uncertainty relation involving min-entropy. The relation is tight and can be applied in various quantum-cryptographic settings. Protocols for quantum 1-out-of-2 Oblivious Transfer and quantum Bit Commitment are presented and the uncertainty relation is used to prove the security of these protocols in the bounded quantum-storage model according to new strong security definitions. As another application, we consider the realistic setting of Quantum Key Distribution (QKD) against quantum-memory-bounded eavesdroppers. The uncertainty relation allows to prove the security of QKD protocols in this setting while tolerating considerably higher error rates compared to the standard model with unbounded adversaries. For instance, for the six-state protocol with one-way communication, a bit-flip error rate of up to 17% can be tolerated (compared to 13% in the standard model). Our uncertainty relation also yields a lower bound on the min-entropy key uncertainty against known-plaintext attacks when quantum ciphers are composed. Previously, the key uncertainty of these ciphers was only known with respect to Shannon entropy.

This mission is the statement-level formalization of A Tight High-Order Entropic Quantum Uncertainty Relation With Applications (arXiv:quant-ph/0612014v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

20 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Theorem 3.3: general high-order entropic uncertainty relation (paper headline) (Theorem 3.3: general high-order entropic uncertainty relation (paper headline), PDF p. 7). The milestones are the other numbered results, in the paper's order, each quoting the paper.

The paper's own objects are the definition item of this mission. Objects shared across papers come from the prove2quantum library and from earlier papers' missions, listed as references.

Provenance: prove2quantum's pipeline drafted each statement (gpt-6.1-sol on Stanford's Sherlock cluster). A blind read-back, written without seeing the paper, is attached to every item. An independent moderator compared each statement against the paper and passed the whole paper without edits.

Deferred results

10 results of the paper are not stated yet, because the library lacks an interface they need:

  • Lemma 2.1: cited smooth classical chain rule: A valid endpoint domain for the printed strict smooth-entropy chain rule (hard)
  • Unnumbered headline application: ordinary 1-out-of-2 OT: Ordinary-input conversion/security execution and the missing positive linear memory slack (source-ambiguity)
  • Unnumbered: security under sequential composition: A sequential composition experiment and operational compatibility theorem (source-ambiguity)
  • Unnumbered: bitwise string commitment from strong bit binding: Joint repeated commitment execution, storage checkpoints, and quantitative string-binding error (source-ambiguity)
  • Unnumbered: general QKD rate lower bound: Figure 3 operational sifting/reconciliation/channel and correctness bridge with sublinear quantum storage and the entire public transcript (source-ambiguity)
  • Theorem 6.1: positive binary-channel QKD rate: Figure 3 operational sifting/reconciliation/channel and correctness bridge with sublinear quantum storage and the entire public transcript (source-ambiguity)
  • Unnumbered: BB84 tolerates 11 percent errors in the bounded-memory model: Figure 3 operational sifting/reconciliation/channel and correctness bridge with sublinear quantum storage and the entire public transcript (source-ambiguity)
  • Unnumbered: six-state QKD tolerates 17 percent errors: Figure 3 operational sifting/reconciliation/channel and correctness bridge with sublinear quantum storage and the entire public transcript (source-ambiguity)
  • Unnumbered: QKD with more bases approaches a 20 percent noise threshold: Finite-basis approximation with a nonzero-sifting operational QKD rate/security bridge (source-ambiguity)
  • Unnumbered main application: composed quantum-cipher min-entropy key uncertainty: Concrete cipher-to-measurement entropy bridge and explicit smoothed composition statement (source-ambiguity)

Selected references

  • A Tight High-Order Entropic Quantum Uncertainty Relation With Applications, arXiv:quant-ph/0612014v2, https://arxiv.org/abs/quant-ph/0612014v2
27 thms2 active usersReviewed
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