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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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Campaigns (experimental)

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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.

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.

≥ 2.1308255793978239Formalized record→≥ 2.15Open frontier
9 provers on it17 of 18 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
4 provers on it7 of 7 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
17 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.
≤ 21Formalized record→≤ 16Open frontier
5 provers on it12 of 13 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.

≤ 27Formalized record→≤ 5Open frontier
38 provers on it13 of 15 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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About Prove2Me

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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Information TheoryQuantum InformationTheoretical Computer Science·Captain: mikedeng1

Improving the Security of Quantum Protocols via Commit-and-Open: After the Commit-and-Open Test, Any Dishonest Bob Is β-Benign Up to a Negligible Trace DistanceResearch Paper

Motivation

Many two-party quantum protocols, such as oblivious transfer and password-based identification, start the same way: Alice sends Bob nnn qubits ∣x⟩θ|x\rangle_\theta∣x⟩θ​ encoding random bits xxx in random BB84 bases θ∈{+,×}n\theta\in\{+,\times\}^nθ∈{+,×}n. Their security proofs work only against a restricted Bob, for example one with bounded quantum memory (Damgård, Fehr, Salvail, Schaffner 2005). Unrestricted security is impossible for such tasks in the plain model.

Damgård, Fehr, Lunemann, Salvail and Schaffner (arXiv:0902.3918, CRYPTO 2009) proposed a generic commit-and-open compiler. Bob commits to his measurement bases θ^\hat\thetaθ^ and outcomes x^\hat xx^ position by position. Alice opens a random fraction α\alphaα of the commitments and checks that xi=x^ix_i=\hat x_ixi​=x^i​ wherever her basis agreed with Bob's. Their headline result, Theorem 4.2, says that the compiled protocol is computationally secure against any polynomial-time Bob. Its proof reduces everything computational to one information-theoretic statement: after the test, a dishonest Bob is β-benign (Definition 4.1), up to a negligible error. The paper's introduction presents this statement as the new tool. This mission formalizes it.

Setting

Alice holds mmm qubits, one half of each of mmm EPR pairs, in a register A=C{0,1}mA=\mathbb C^{\{0,1\}^m}A=C{0,1}m. Bob holds an arbitrary finite-dimensional register EEE. The joint state right before the test is an arbitrary unit vector ∣φAE⟩∈HA⊗HE|\varphi_{AE}\rangle\in\mathcal H_A\otimes\mathcal H_E∣φAE​⟩∈HA​⊗HE​. This is the state after a dishonest Bob has received his halves and committed to x^∈{0,1}m\hat x\in\{0,1\}^mx^∈{0,1}m and θ^∈{+,×}m\hat\theta\in\{+,\times\}^mθ^∈{+,×}m.

The test is a pair (T,T′)(T,T')(T,T′). TTT is a uniformly random set of k=⌊αm⌋k=\lfloor\alpha m\rfloork=⌊αm⌋ positions; T′={i∈T:θi=θ^i}T'=\{i\in T:\theta_i=\hat\theta_i\}T′={i∈T:θi​=θ^i​} for Alice's uniform bases θ\thetaθ is a uniform subset of TTT. So PTest(T,T′)=1/((mk)2k)P_{Test}(T,T')=1/(\binom mk 2^k)PTest​(T,T′)=1/((km​)2k). In the analysed version of the protocol (Fig. 4), Alice measures the positions in TTT in Bob's bases θ^∣T\hat\theta|_Tθ^∣T​ and accepts iff xi=x^ix_i=\hat x_ixi​=x^i​ for all i∈T′i\in T'i∈T′. She then measures the remaining n=m−kn=m-kn=m−k positions in her bases θ∣Tˉ\theta|_{\bar T}θ∣Tˉ​, producing XXX.

The quantities of interest are:

  • the min-entropy H∞(X)=−log⁡2max⁡xPX(x)H_\infty(X)=-\log_2\max_xP_X(x)H∞​(X)=−log2​maxx​PX​(x) and its conditional version H∞(X∣I∣X∣Iˉ=x∣Iˉ)H_\infty(X|_I\mid X|_{\bar I}=x|_{\bar I})H∞​(X∣I​∣X∣Iˉ​=x∣Iˉ​);
  • the max-entropy H0(ρ)=log⁡2rank⁡ρH_0(\rho)=\log_2\operatorname{rank}\rhoH0​(ρ)=log2​rankρ;
  • the Hamming distance dHd_HdH​ and the relative distance rH=dH/lengthr_H=d_H/\text{length}rH​=dH​/length;
  • the trace distance δ(ρ,σ)=12tr⁡∣ρ−σ∣\delta(\rho,\sigma)=\tfrac12\operatorname{tr}|\rho-\sigma|δ(ρ,σ)=21​tr∣ρ−σ∣;
  • the binary entropy h(μ)=−(μlog⁡2μ+(1−μ)log⁡2(1−μ))h(\mu)=-(\mu\log_2\mu+(1-\mu)\log_2(1-\mu))h(μ)=−(μlog2​μ+(1−μ)log2​(1−μ)).

A function ν(m)\nu(m)ν(m) is negligible if ∣ν(m)∣≤m−c|\nu(m)|\le m^{-c}∣ν(m)∣≤m−c for every ccc and all large mmm.

The real cq state is ρTestAE=∑testPTest(test)∣test⟩⟨test∣⊗∣φAE⟩⟨φAE∣\rho_{TestAE}=\sum_{test}P_{Test}(test)|test\rangle\langle test|\otimes|\varphi_{AE}\rangle\langle\varphi_{AE}|ρTestAE​=∑test​PTest​(test)∣test⟩⟨test∣⊗∣φAE​⟩⟨φAE​∣. The set

Btest={x:rH(x∣Tˉ,x^∣Tˉ)≤rH(x∣T′,x^∣T′)+ε}B_{test}=\{x: r_H(x|_{\bar T},\hat x|_{\bar T})\le r_H(x|_{T'},\hat x|_{T'})+\varepsilon\}Btest​={x:rH​(x∣Tˉ​,x^∣Tˉ​)≤rH​(x∣T′​,x^∣T′​)+ε}

collects the outcomes whose error rate on the unopened positions is predicted by the error rate on T′T'T′.

Formalization targets

Goal: commit-and-open forces benign behaviour (§4.3, p. 12)

For every 0<α<10<\alpha<10<α<1 and β>0\beta>0β>0 there is a negligible ν\nuν such that, for every mmm, x^\hat xx^, θ^\hat\thetaθ^, finite EEE and unit ∣φAE⟩|\varphi_{AE}\rangle∣φAE​⟩, there are unit vectors ∣φ~AEtest⟩|\tilde\varphi^{test}_{AE}\rangle∣φ~​AEtest​⟩ with

δ(ρTestAE, ∑testPTest(test)∣test⟩⟨test∣⊗∣φ~AEtest⟩⟨φ~AEtest∣)≤ν(m),\delta\Big(\rho_{TestAE},\ \sum_{test}P_{Test}(test)|test\rangle\langle test|\otimes|\tilde\varphi^{test}_{AE}\rangle\langle\tilde\varphi^{test}_{AE}|\Big)\le\nu(m),δ(ρTestAE​, test∑​PTest​(test)∣test⟩⟨test∣⊗∣φ~​AEtest​⟩⟨φ~​AEtest​∣)≤ν(m),

and such that, in the ideal state, every branch Alice accepts satisfies the bounds (1) of Definition 4.1:

H∞(X∣I∣X∣Iˉ=x∣Iˉ)≥dH(θ∣I,θ^∣I)−βn,H0(ρER)≤βn.H_\infty\big(X|_I\mid X|_{\bar I}=x|_{\bar I}\big)\ge d_H(\theta|_I,\hat\theta|_I)-\beta n,\qquad H_0(\rho_{ER})\le\beta n.H∞​(X∣I​∣X∣Iˉ​=x∣Iˉ​)≥dH​(θ∣I​,θ^∣I​)−βn,H0​(ρER​)≤βn.

No constant is hard-coded; β\betaβ is arbitrary.

Milestones

  • Lemma 2.3: measuring a superposition of ∣J∣|J|∣J∣ product vectors loses at most log⁡∣J∣\log|J|log∣J∣ bits of min-entropy, and leaves Bob's register with rank at most ∣J∣|J|∣J∣.
  • The trace distance of pure states, 1−∣⟨ψ∣φ⟩∣2\sqrt{1-|\langle\psi|\varphi\rangle|^2}1−∣⟨ψ∣φ⟩∣2​.
  • The trace distance of two cq states over TestTestTest is the PTestP_{Test}PTest​-average of the branch distances.
  • The classical sampling bound: Pr⁡test[x∉Btest]\Pr_{test}[x\notin B_{test}]Prtest​[x∈/Btest​] is negligible, uniformly in xxx.
  • Lemma 4.3: ρTestAE\rho_{TestAE}ρTestAE​ is negligibly close to a state each of whose branches is supported on BtestB_{test}Btest​ in Bob's basis.
  • The Hamming-ball bound ∣{y:dH(y,y^)≤μn}∣≤2h(μ)n|\{y:d_H(y,\hat y)\le\mu n\}|\le2^{h(\mu)n}∣{y:dH​(y,y^​)≤μn}∣≤2h(μ)n for 0≤μ≤120\le\mu\le\tfrac120≤μ≤21​.
  • Corollary 4.4: on such a branch, H∞≥dH−h(err+ε)nH_\infty\ge d_H-h(err+\varepsilon)nH∞​≥dH​−h(err+ε)n and H0≤h(err+ε)nH_0\le h(err+\varepsilon)nH0​≤h(err+ε)n, where errerrerr is the error rate on T′T'T′.

Significance

The goal is what makes the compiler work. Combined with the security of the original protocol against benign Bob, it turns any BB84-type protocol that is secure in a restricted model into one secure against arbitrary dishonest Bob in the computational setting. The paper derives oblivious transfer and password-based identification this way (§6). The same statement also preserves bounded-quantum-storage security (§5.2). Its quantitative form, β=h(err+ε)\beta=h(err+\varepsilon)β=h(err+ε), shows how noise tolerance enters (§5.1).

The paper's headline Theorem 4.2 is computational: it quantifies over polynomial-time quantum adversaries and simulators in the common-reference-string model, with a dual-mode commitment scheme specified in prose. That wrapper is out of scope. The unconditional core claim, closing §4.3, is a statement about finite-dimensional states, entropies and a sampling distribution. To our knowledge no machine-checked proof of it, of Lemma 4.3, or of Corollary 4.4 exists. Formalizing it also produces reusable pieces: min- and max-entropy of superpositions, trace distance of pure and cq states, and a sampling bound for random subsets.

Difficulty

The statement mixes a quantum and a classical argument, and neither carries the whole weight. The obvious attempt, applying an entropic uncertainty relation directly to Bob's state, fails: Bob's register may be entangled with all of Alice's qubits, so nothing bounds its rank a priori. The bound appears only after the real state is replaced by a nearby one, and that replacement must be uniform over Bob's register and strategy. Uniformity is the delicate point: the negligible function must not depend on mmm, x^\hat xx^, θ^\hat\thetaθ^ or the state.

The sampling step concerns sampling without replacement (TTT of fixed size), followed by an independent subsample T′T'T′ that can be empty. The entropy bounds then need the Hamming-ball estimate at the real radius (err+ε)n(err+\varepsilon)n(err+ε)n, valid only up to 12\tfrac1221​.

Formalization scope

  • Registers are C{0,1}m\mathbb C^{\{0,1\}^m}C{0,1}m (EuclideanSpace ℂ (Fin m → Bool)) and CE\mathbb C^ECE for a finite type E. Joint states are unit vectors of the product. The joint state is pure, which the paper argues is without loss of generality: a mixed state is purified and the purifier joins EEE.
  • Bits are Bool; bases are Bool with false = +++, true = ×\times×. Positions are 0-based Fin m.
  • ∣T∣=⌊αm⌋|T|=\lfloor\alpha m\rfloor∣T∣=⌊αm⌋ and n=m−⌊αm⌋n=m-\lfloor\alpha m\rfloorn=m−⌊αm⌋; these match the paper's αm\alpha mαm and (1−α)m(1-\alpha)m(1−α)m whenever αm\alpha mαm is an integer.
  • log⁡=log⁡2\log=\log_2log=log2​. hhh is Mathlib's Real.binEntropy divided by ln⁡2\ln2ln2. The trace norm is the published WildeQIT.traceNorm, and the trace distance carries the factor 12\tfrac1221​.
  • Alice's two measurements (in θ^\hat\thetaθ^ on TTT, in θ\thetaθ on Tˉ\bar TTˉ) are encoded as one measurement in the mixed basis. Conditional min-entropies condition on x∣Tx|_Tx∣T​ as well.
  • Bob's post-measurement state is kept unnormalized, which leaves its rank unchanged. Statements that condition on an outcome assume it has positive probability.
  • rHr_HrH​ on the empty set is 000.
  • Corollary 4.4 assumes err+ε≤12err+\varepsilon\le\tfrac12err+ε≤21​. The printed err≤12err\le\tfrac12err≤21​ is not sufficient: at err=ε=12err=\varepsilon=\tfrac12err=ε=21​ the conclusion fails. The goal is unaffected.
  • The ideal vectors in the goal depend on the test only, and one ν\nuν serves all mmm, x^\hat xx^, θ^\hat\thetaθ^, EEE and states. Neither conclusion is trivial on its own: taking the ideal state equal to the real one gives distance 000, and taking it to be the honest state ∣x^⟩θ^⊗∣e⟩|\hat x\rangle_{\hat\theta}\otimes|e\rangle∣x^⟩θ^​⊗∣e⟩ satisfies (1). The goal demands both at once.

Contributions are welcome on any milestone. The sampling bound and the pure-state and block-diagonal trace-distance identities are independent of the rest. The trace-norm lemmas and the Hamming-ball bound are useful beyond this mission.

Selected references

  • I. Damgård, S. Fehr, C. Lunemann, L. Salvail, C. Schaffner, Improving the Security of Quantum Protocols via Commit-and-Open, CRYPTO 2009; arXiv:0902.3918v4. https://arxiv.org/abs/0902.3918
  • I. Damgård, S. Fehr, L. Salvail, C. Schaffner, Cryptography in the Bounded Quantum-Storage Model, FOCS 2005. https://arxiv.org/abs/quant-ph/0508222
  • W. Hoeffding, Probability Inequalities for Sums of Bounded Random Variables, J. Amer. Statist. Assoc. 58 (1963). https://doi.org/10.1080/01621459.1963.10500830
  • S. Fehr, C. Schaffner, Composing Quantum Protocols in a Classical Environment, TCC 2009. https://arxiv.org/abs/0804.1059
11 thms2 active usersReviewed
Dynamical SystemsMathematical PhysicsQuantum Information·Captain: mikedeng1

Highly Efficient Energy Excitation Transfer in Light-Harvesting Complexes: The Fundamental Role of Noise-Assisted Transport: Sink Population 1/(N−1) Without Noise, 1 Under DephasingResearch Paper

Motivation

Photosynthetic light-harvesting complexes move an electronic excitation from the pigment that absorbed a photon to a reaction centre, where its energy is stored chemically. In the Fenna–Matthews–Olson (FMO) complex this transfer is close to lossless, and two-dimensional spectroscopy showed long-lived quantum coherence during it (Engel et al. 2007). This raised a concrete question in open-system quantum dynamics: does the environment, whose noise destroys coherence, hinder transport, or can it help?

Numerical studies of FMO models found that local dephasing raises transfer efficiency compared with purely coherent evolution (Mohseni et al. 2008; Plenio and Huelga 2008; Rebentrost et al. 2009). Caruso, Chin, Datta, Huelga and Plenio (arXiv:0901.4454, J. Chem. Phys. 2009) isolated a mechanism behind this in a model that can be solved exactly: the fully connected network (FCN). There, coherent evolution traps most of the excitation by destructive interference, and any amount of uniform dephasing removes the trap. This mission formalizes that exact result.

Setting

The network has NNN sites. The single-excitation space has orthonormal basis ∣0⟩,∣1⟩,…,∣N⟩,∣N+1⟩|0\rangle, |1\rangle, \dots, |N\rangle, |N+1\rangle∣0⟩,∣1⟩,…,∣N⟩,∣N+1⟩: ∣0⟩|0\rangle∣0⟩ is the zero-exciton state (population lost to the environment), ∣j⟩|j\rangle∣j⟩ for 1≤j≤N1 \le j \le N1≤j≤N is one excitation on site jjj, and ∣N+1⟩|N+1\rangle∣N+1⟩ is the sink (the reaction centre). The operators σj+=∣j⟩⟨0∣\sigma_j^+ = |j\rangle\langle 0|σj+​=∣j⟩⟨0∣ and σj−=∣0⟩⟨j∣\sigma_j^- = |0\rangle\langle j|σj−​=∣0⟩⟨j∣ create and destroy the excitation on site jjj.

The FCN Hamiltonian HHH (with ℏ=1\hbar = 1ℏ=1) has ⟨j∣H∣j⟩=ωj\langle j|H|j\rangle = \omega_j⟨j∣H∣j⟩=ωj​, the site energies, and ⟨i∣H∣j⟩=J\langle i|H|j\rangle = J⟨i∣H∣j⟩=J for every pair of distinct sites, and vanishes on ∣0⟩|0\rangle∣0⟩ and ∣N+1⟩|N+1\rangle∣N+1⟩. For a real rate rrr and an operator ccc write

Dr,c(ρ)=r [2cρc†−{c†c,ρ}].\mathcal D_{r,c}(\rho) = r\,\bigl[2c\rho c^\dagger - \{c^\dagger c, \rho\}\bigr].Dr,c​(ρ)=r[2cρc†−{c†c,ρ}].

The state ρ(t)\rho(t)ρ(t), a complex (N+2)×(N+2)(N+2)\times(N+2)(N+2)×(N+2) matrix, obeys the Lindblad master equation ρ˙=L(ρ)\dot\rho = \mathcal L(\rho)ρ˙​=L(ρ) with

L(ρ)=−i[H,ρ]+∑j=1NDΓj, σj−(ρ)+∑j=1NDγj, ∣j⟩⟨j∣(ρ)+DΓN+1, ∣N+1⟩⟨k∣(ρ).\mathcal L(\rho) = -i[H,\rho] + \sum_{j=1}^N \mathcal D_{\Gamma_j,\,\sigma_j^-}(\rho) + \sum_{j=1}^N \mathcal D_{\gamma_j,\,|j\rangle\langle j|}(\rho) + \mathcal D_{\Gamma_{N+1},\,|N+1\rangle\langle k|}(\rho).L(ρ)=−i[H,ρ]+j=1∑N​DΓj​,σj−​​(ρ)+j=1∑N​Dγj​,∣j⟩⟨j∣​(ρ)+DΓN+1​,∣N+1⟩⟨k∣​(ρ).

The terms are coherent hopping, dissipation to the environment at rates Γj\Gamma_jΓj​, pure dephasing at rates γj\gamma_jγj​, and irreversible decay into the sink from a chosen site kkk at rate ΓN+1\Gamma_{N+1}ΓN+1​. So ρ(t)=etLρ(0)\rho(t) = e^{t\mathcal L}\rho(0)ρ(t)=etLρ(0). The initial state is ρ(0)=∣1⟩⟨1∣\rho(0) = |1\rangle\langle 1|ρ(0)=∣1⟩⟨1∣, and transport is measured by the sink population

psink(t)=2ΓN+1∫0tρkk(t′) dt′.p_{\rm sink}(t) = 2\Gamma_{N+1}\int_0^t \rho_{kk}(t')\,dt'.psink​(t)=2ΓN+1​∫0t​ρkk​(t′)dt′.

The goal concerns the FCN of §II.A: ωj=0\omega_j = 0ωj​=0, Γj=0\Gamma_j = 0Γj​=0, the sink attached at k=Nk = Nk=N, and a uniform dephasing rate γj=γ≥0\gamma_j = \gamma \ge 0γj​=γ≥0.

Formalization targets

Goal: noise-free and dephased limits

For N≥2N \ge 2N≥2, J≠0J \ne 0J=0 and ΓN+1>0\Gamma_{N+1} > 0ΓN+1​>0:

γ=0:lim⁡t→∞psink(t)=1N−1,γ>0:lim⁡t→∞psink(t)=1.\gamma = 0:\quad \lim_{t\to\infty} p_{\rm sink}(t) = \frac{1}{N-1}, \qquad\qquad \gamma > 0:\quad \lim_{t\to\infty} p_{\rm sink}(t) = 1.γ=0:t→∞lim​psink​(t)=N−11​,γ>0:t→∞lim​psink​(t)=1.

The first limit is Eq. (5) of the paper. The second is the claim of §II.C, confirmed for uniform dephasing in Appendix A.3, Eq. (A30). The coupling JJJ, the sink rate and the dephasing rate are left free; neither limit depends on them.

Milestones

  1. (A7) Population sum rule: 1=∑j=1Nρjj(t)+ρ00(t)+psink(t)1 = \sum_{j=1}^N \rho_{jj}(t) + \rho_{00}(t) + p_{\rm sink}(t)1=∑j=1N​ρjj​(t)+ρ00​(t)+psink​(t) for all ttt.
  2. §II.A spectrum. ∣ϕ⟩=N−1/2∑j∣j⟩|\phi\rangle = N^{-1/2}\sum_j |j\rangle∣ϕ⟩=N−1/2∑j​∣j⟩ has energy J(N−1)J(N-1)J(N−1). The states ∣ψj⟩=∣1⟩−∣j⟩|\psi_j\rangle = |1\rangle - |j\rangle∣ψj​⟩=∣1⟩−∣j⟩, j=2,…,Nj = 2,\dots,Nj=2,…,N, have energy −J-J−J, and together with ∣ϕ⟩|\phi\rangle∣ϕ⟩ they span the site space.
  3. Eq. (8). ∣1⟩=1N−1[∑j=2N−1∣ψj⟩+N∣ϕ⟩−∣N⟩]|1\rangle = \frac{1}{N-1}\bigl[\sum_{j=2}^{N-1}|\psi_j\rangle + \sqrt N|\phi\rangle - |N\rangle\bigr]∣1⟩=N−11​[∑j=2N−1​∣ψj​⟩+N​∣ϕ⟩−∣N⟩].
  4. Invariant states. In the noiseless FCN, an eigenstate of HHH with no overlap with site NNN does not evolve, and psink≡0p_{\rm sink} \equiv 0psink​≡0.
  5. Eqs. (6)–(7). For N≥3N \ge 3N≥3, ρ(t)→N−2N−1∣Ψ⟩⟨Ψ∣+1N−1∣N+1⟩⟨N+1∣\rho(t) \to \frac{N-2}{N-1}|\Psi\rangle\langle\Psi| + \frac1{N-1}|N+1\rangle\langle N+1|ρ(t)→N−1N−2​∣Ψ⟩⟨Ψ∣+N−11​∣N+1⟩⟨N+1∣.
  6. (A14). The closed form of ρNN(t)\rho_{NN}(t)ρNN​(t) for the noiseless FCN, N≥3N \ge 3N≥3.
  7. Appendix A.1. The closed linear system of six equations for Λ=∑i,jρij\Lambda = \sum_{i,j}\rho_{ij}Λ=∑i,j​ρij​, X+iY=∑jρNjX + iY = \sum_j \rho_{Nj}X+iY=∑j​ρNj​, ρNN\rho_{NN}ρNN​, ρ00\rho_{00}ρ00​ and psinkp_{\rm sink}psink​ under uniform ω\omegaω, Γ\GammaΓ, γ\gammaγ.

Significance

The result. The noise-free limit 1/(N−1)1/(N-1)1/(N−1) shows that a perfectly coherent, fully symmetric network is a poor transporter: for N=10N = 10N=10 only 1/91/91/9 of the excitation reaches the sink, whereas a classical random walk on the same graph delivers all of it. The dephased limit 111 shows that arbitrarily weak local noise restores complete transfer. Together they are the cleanest exactly solvable instance of dephasing-assisted transport. The invariant-subspace argument behind them (milestones 2–5) also predicts which states are protected from a sink, a mechanism related to coherent population trapping in quantum optics and condensed-matter systems.

Formalizing it. The paper derives these limits from Laplace-domain calculations and residue computations, some of them only sketched. A machine-checked proof would settle the exact constants, the hypotheses under which each limit holds (the necessity of J≠0J \ne 0J=0 and ΓN+1>0\Gamma_{N+1} > 0ΓN+1​>0, and the case N=2N = 2N=2), and the passage from the matrix exponential to the collective variables. As far as is known, none of these results has been formalized. The development also produces reusable pieces: the Lindblad generator of a single-excitation network with a sink, the trace identity (A7), and the spectrum of the complete-graph hopping Hamiltonian.

Difficulty

The obvious route is to compute etLe^{t\mathcal L}etL, but L\mathcal LL acts on an (N+2)2(N+2)^2(N+2)2-dimensional space for arbitrary NNN, so no fixed-size computation applies. The noise-free limit hinges on an exact cancellation: N−2N−1\frac{N-2}{N-1}N−1N−2​ of the weight lies in an HHH-eigenspace that is invisible to the sink, and the remainder must be shown to drain completely, which is a statement about the spectrum of a non-normal generator on the complementary subspace. Under dephasing that invariant subspace no longer exists, but the reduced six-variable system still has to be shown to have psink=1p_{\rm sink} = 1psink​=1 as its only attracting steady state, for every γ>0\gamma > 0γ>0 and every NNN. In the paper this is done through a final-value theorem applied to a fifth-order characteristic polynomial (A26), which is misprinted. A proof that the limit exists, and not only what it equals, is part of the task.

Formalization scope

  • Basis and operators. The basis is Fin (N + 2) in the paper's numbering (0 = zero-exciton state, 1…N = sites, N + 1 = sink), with natural-number indices cast into it. Operators are Matrix (Fin (N + 2)) (Fin (N + 2)) ℂ.
  • Hopping and rates. The hopping is normalized as ⟨i∣H∣j⟩=J\langle i|H|j\rangle = J⟨i∣H∣j⟩=J, which matches (A1), (A34) and the spectrum on p. 4. The rates multiply 2cρc†−{c†c,ρ}2c\rho c^\dagger - \{c^\dagger c,\rho\}2cρc†−{c†c,ρ} with no factor ½, as in Eqs. (2)–(4).
  • Evolution. ρ(t)\rho(t)ρ(t) is semigroupEvolution of the published definition P16, that is, NormedSpace.exp of tLt\mathcal LtL, applied to ∣1⟩⟨1∣|1\rangle\langle 1|∣1⟩⟨1∣.
  • Sink population. psinkp_{\rm sink}psink​ is the interval integral of the real part of ρkk\rho_{kk}ρkk​, as defined on p. 3. It is not the sink entry ρN+1,N+1\rho_{N+1,N+1}ρN+1,N+1​; that the two agree is part of milestone 1.
  • Added hypotheses. The goal assumes N≥2N \ge 2N≥2, J≠0J \ne 0J=0 and ΓN+1>0\Gamma_{N+1} > 0ΓN+1​>0; without any one of them the limits fail. Milestones 5 and 6 assume N≥3N \ge 3N≥3, where ∣Ψ⟩|\Psi\rangle∣Ψ⟩ and the closed form are defined.
  • Uniform dephasing. The dephased clause is stated only for a uniform rate γj=γ\gamma_j = \gammaγj​=γ, which is the case the paper solves. It is quantified over every γ>0\gamma > 0γ>0.

A trivializing formalization is ruled out by construction: NNN and γ\gammaγ are free, psinkp_{\rm sink}psink​ unfolds to an integral of an entry of the matrix exponential of the literal generator, and none of the limits is built into a definition.

Needed infrastructure includes calculus for t↦etLXt \mapsto e^{tL}Xt↦etLX (derivatives, HasDerivAt of entries, the fundamental theorem of calculus for psinkp_{\rm sink}psink​), invariant-subspace arguments for linear ODEs, and asymptotics of linear systems with a stable matrix. Contributions of general lemmas about Lindblad semigroups (trace preservation, Hermiticity preservation, stationary states) are welcome and reusable beyond this mission.

Not formalized here: Eq. (9) (static disorder), Eq. (10) (dissipation), §II.D–§V, the Laplace-domain route (A9)–(A13) and (A25)–(A29), the two-level system (A32), and the general networks of (A39)–(A40).

Selected references

  • F. Caruso, A. W. Chin, A. Datta, S. F. Huelga, M. B. Plenio, Highly efficient energy excitation transfer in light-harvesting complexes: The fundamental role of noise-assisted transport, J. Chem. Phys. 131, 105106 (2009). https://arxiv.org/abs/0901.4454v2 — https://doi.org/10.1063/1.3223548
  • G. S. Engel et al., Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems, Nature 446, 782 (2007). https://doi.org/10.1038/nature05678
  • M. Mohseni, P. Rebentrost, S. Lloyd, A. Aspuru-Guzik, Environment-assisted quantum walks in photosynthetic energy transfer, J. Chem. Phys. 129, 174106 (2008). https://doi.org/10.1063/1.3002335
  • M. B. Plenio, S. F. Huelga, Dephasing-assisted transport: quantum networks and biomolecules, New J. Phys. 10, 113019 (2008). https://doi.org/10.1088/1367-2630/10/11/113019
  • P. Rebentrost, M. Mohseni, I. Kassal, S. Lloyd, A. Aspuru-Guzik, Environment-assisted quantum transport, New J. Phys. 11, 033003 (2009). https://doi.org/10.1088/1367-2630/11/3/033003
  • G. Lindblad, On the generators of quantum dynamical semigroups, Commun. Math. Phys. 48, 119 (1976). https://doi.org/10.1007/BF01608499
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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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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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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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Entanglement-Assisted Classical Capacity of Noisy Quantum ChannelsResearch Paper

Motivation

Prior entanglement between sender and receiver, which exactly doubles the classical capacity of a noiseless quantum channel, can increase the classical capacity of some noisy quantum channels by an arbitrarily large constant factor depending on the channel, relative to the best known classical capacity achievable without entanglement. The enhancement factor is greatest for very noisy channels, with positive classical capacity but zero quantum capacity. Although such quantum channels can be simulated classically, no violation of causality is implied, because the simulation requires at least as much forward classical communication as the entanglement-assisted classical capacity of the channel being simulated. We obtain exact expressions for the entanglement-assisted capacity of depolarizing and erasure channels in d dimensions.

This mission is the statement-level formalization of Entanglement-Assisted Classical Capacity of Noisy Quantum Channels (arXiv:quant-ph/9904023v5). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

14 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Abstract main result / equation (3): depolarizing assisted capacity (Abstract main result / equation (3): depolarizing assisted capacity, 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:

  • Unnumbered C <= CE <= FCCC: A resource-counted finite adaptive bipartite channel-simulation model with arbitrary local ancillas, message-independent prior pure entanglement, free backward classical communication, an actual forward classical arm, and asymptotically faithful reference-preserving simulation. (hard)
  • Erasure flags simulate depolarization and all corresponding capacity inequalities: Source-compatible Q2 from counted noisy-channel calls interleaved with adaptive finite LOCC, initially with no shared entanglement. (hard)
  • Again the difference between the bounds approaches H2(x): A source-pinned noise regime for the asserted limit of the signed quantum-bound gap. (source-ambiguity)
  • Author note [9]: A transpose/label convention or restriction making the three induced classical transition matrices literally identical. (source-ambiguity)

Selected references

  • Entanglement-Assisted Classical Capacity of Noisy Quantum Channels, arXiv:quant-ph/9904023v5, https://arxiv.org/abs/quant-ph/9904023v5
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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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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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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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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
32 thms2 active usersReviewed
Quantum Information·Captain: Goku

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
9 thms2 active usersReviewed
Quantum Information·Captain: Goku

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
12 thms2 active usersReviewed
Quantum Information·Captain: Goku

The capacity of the quantum depolarizing channelResearch Paper

Motivation

The information carrying capacity of the d-dimensional depolarizing channel is computed. It is shown that this capacity can be achieved by encoding messages as products of pure states belonging to an orthonormal basis of the state space, and using measurements which are products of projections onto this same orthonormal basis. In other words, neither entangled signal states nor entangled measurements give any advantage for information capacity. The result follows from an additivity theorem for the capacity of the product of the depolarizing channel with an arbitrary channel. We establish the Amosov-Holevo-Werner p-norm conjecture for this product channel for all p >= 1, and deduce from this the additivity of the minimal entropy and of the Holevo quantity.

This mission is the statement-level formalization of The capacity of the quantum depolarizing channel (arXiv:quant-ph/0204172v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

14 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Depolarizing channel: exact unassisted classical capacity (Theorem 1 / abstract: exact unassisted classical capacity and basis strategy, 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.

Selected references

  • The capacity of the quantum depolarizing channel, arXiv:quant-ph/0204172v2, https://arxiv.org/abs/quant-ph/0204172v2
24 thms2 active usersReviewed
Quantum Information·Captain: Goku

Capacities of Quantum Erasure ChannelsResearch Paper

Motivation

The quantum analog of the classical erasure channel provides a simple example of a channel whose asymptotic capacity for faithful transmission of intact quantum states, with and without the assistance of a two-way classical side channel, can be computed exactly. We derive the quantum and classical capacities for the quantum erasure channel and related channels, and compare them to the depolarizing channel, for which only upper and lower bounds on the capacities are known.

This mission is the statement-level formalization of Capacities of Quantum Erasure Channels (arXiv:quant-ph/9701015v2). 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 Exact capacities of the qubit quantum erasure channel (Eq. (2), PDF p. 2). 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

  • Capacities of Quantum Erasure Channels, arXiv:quant-ph/9701015v2, https://arxiv.org/abs/quant-ph/9701015v2
13 thms2 active usersReviewed
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
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
13 thms2 active usersReviewed
Quantum Information·Captain: Goku

An additive and operational entanglement measure: conditional entanglement of mutual informationResearch Paper

Motivation

Based on the monogamy of entanglement, we develop the technique of quantum conditioning to build an {\it additive} entanglement measure: the conditional entanglement of mutual information. Its {\it operational} meaning is elaborated to be the minimal net "flow of qubits" in the process of partial state merging. The result and conclusion can also be generalized to multipartite entanglement cases.

This mission is the statement-level formalization of An additive and operational entanglement measure: conditional entanglement of mutual information (arXiv:0804.3683v2). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

12 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Proposition 1: bipartite additivity (Proposition 1: bipartite additivity (the page-1 seed pinned to its numbered theorem), 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:

  • Unnumbered: fixed-extension partial state merging cost and route independence: Admissible resource/protocol class and ancillary-work accounting for the signed net-qubit PSM/PSD minimum (source-ambiguity)
  • Proposition 2: CEMI as optimized partial state merging cost: Admissible resource/protocol class and ancillary-work accounting for the signed net-qubit PSM/PSD minimum (source-ambiguity)
  • Proposition 4: multipartite CEMI as optimized partial state merging cost: Admissible resource/protocol class and ancillary-work accounting for the signed net-qubit PSM/PSD minimum (source-ambiguity)
  • Unnumbered: reversed process partial state distribution: Admissible resource/protocol class and ancillary-work accounting for the signed net-qubit PSM/PSD minimum (source-ambiguity)

Selected references

  • An additive and operational entanglement measure: conditional entanglement of mutual information, arXiv:0804.3683v2, https://arxiv.org/abs/0804.3683v2
16 thms2 active usersReviewed
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
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Partial Differential EquationsSymplectic Geometry·Captain: Mazecto

Lectures on Symplectic Field Theory VIII: Asymptotic Analysis of Finite-Energy Pseudoholomorphic CurvesTextbook

Motivation

A finite-energy pseudoholomorphic curve in the symplectization R×S\mathbb{R}\times SR×S of a strictly star-shaped hypersurface S⊂R2n+2S\subset\mathbb{R}^{2n+2}S⊂R2n+2 approaches, near a non-removable puncture, a periodic Reeb orbit P=(x,T)P=(x,T)P=(x,T). The previous mission in this series formalizes this in the form of C. Wendl's Lectures on Symplectic Field Theory, Theorem 9.8: along suitable sequences of loops around the puncture the curve converges to the orbit. Most applications need much more precise information about the end. H. Hofer, K. Wysocki and E. Zehnder showed in 1996 (Ann. IHP 13) that at a nondegenerate orbit the convergence holds for the whole end and is exponentially fast, and that the leading term of the difference is eμse^{\mu s}eμs times an eigenvector of the asymptotic operator APA_PAP​; R. Siefring sharpened the formula to its present form. The asymptotic eigenvector is the input for winding numbers, fast planes and the intersection theory of punctured curves, for example in U. Hryniewicz's characterization of the Reeb orbits that bound disk-like global surfaces of section (arXiv:1105.2077).

This mission formalizes these asymptotic results in general dimension, in the setting of the previous mission. It follows Hryniewicz, Systems of global surfaces of section for dynamically convex Reeb flows on the 3-sphere, § 2.2.3 (Definitions 2.5 and 2.9, Theorem 2.11, Lemma 2.12), and the linear theory of C. Wendl's Lectures on Symplectic Field Theory (2026 notes, §§ 4.6 and 4.8). It is the eighth mission in a series on symplectic field theory.

Setting

All objects are those of FiniteEnergyPlane_Setting: V=R2n+2V=\mathbb{R}^{2n+2}V=R2n+2, a strictly star-shaped level S=H−1(1)S=H^{-1}(1)S=H−1(1) with Reeb field RRR and contact planes ξ\xiξ, a compatible complex structure JJJ on ξ\xiξ, the symplectization structure J~\tilde JJ~ on V∖{0}≅R×SV\setminus\{0\}\cong\mathbb{R}\times SV∖{0}≅R×S, and finite-energy curves.

  • Linearized Reeb flow. Along a periodic Reeb orbit P=(x,T)P=(x,T)P=(x,T), Φ(0)=id\Phi(0)=\mathrm{id}Φ(0)=id and Φ′(τ)=DR(x(τ)) Φ(τ)\Phi'(\tau)=DR(x(\tau))\,\Phi(\tau)Φ′(τ)=DR(x(τ))Φ(τ). PPP is nondegenerate if Φ(T)\Phi(T)Φ(T) fixes no nonzero vector of ξx(0)\xi_{x(0)}ξx(0)​.
  • Asymptotic operator. On smooth 111-periodic loops η\etaη with η(t)∈ξx(Tt)\eta(t)\in\xi_{x(Tt)}η(t)∈ξx(Tt)​, APη(t)=J(x(Tt))(−η′(t)+T DR(x(Tt)) η(t))A_P\eta(t)=J(x(Tt))\big(-\eta'(t)+T\,DR(x(Tt))\,\eta(t)\big)AP​η(t)=J(x(Tt))(−η′(t)+TDR(x(Tt))η(t)) (Hryniewicz, Definition 2.5).
  • Cylindrical ends. At the puncture 000 of a curve on the punctured disk, (s,t)↦e−2π(s+it)(s,t)\mapsto e^{-2\pi(s+it)}(s,t)↦e−2π(s+it); at ∞\infty∞ for a plane, (s,t)↦e2π(s+it)(s,t)\mapsto e^{2\pi(s+it)}(s,t)↦e2π(s+it). Along an end, a(s,t)a(s,t)a(s,t) and w(s,t)∈Sw(s,t)\in Sw(s,t)∈S are the two components of the curve.
  • Nondegenerate puncture (Hryniewicz, Definition 2.9): for a sign ε=±1\varepsilon=\pm1ε=±1 and constants c,dc,dc,d and b>0b>0b>0, a(s,t)−εTs−d→0a(s,t)-\varepsilon Ts-d\to0a(s,t)−εTs−d→0 and ebs(w(s,t)−x(εTt+c))→0e^{bs}\big(w(s,t)-x(\varepsilon Tt+c)\big)\to0ebs(w(s,t)−x(εTt+c))→0 uniformly in ttt. The orbit PPP itself need not be nondegenerate.
  • Asymptotic eigenvector. An eigenvalue μ\muμ of APA_PAP​ with εμ<0\varepsilon\mu<0εμ<0 and an eigenvector vvv such that, in the tube (τ,h)↦proj(x(τ)+h)(\tau,h)\mapsto\mathrm{proj}(x(\tau)+h)(τ,h)↦proj(x(τ)+h) with h∈ξx(τ)h\in\xi_{x(\tau)}h∈ξx(τ)​, the end is w=proj(x(τ)+eεμs(v(τ/T)+r))w=\mathrm{proj}\big(x(\tau)+e^{\varepsilon\mu s}(v(\tau/T)+r)\big)w=proj(x(τ)+eεμs(v(τ/T)+r)) with τ−εTt−c→0\tau-\varepsilon Tt-c\to0τ−εTt−c→0 and r→0r\to0r→0 in C∞C^\inftyC∞.

Formalization targets

Goal: asymptotic eigenvalue and eigenvector at a nondegenerate puncture

Let uuu be a finite-energy J~\tilde JJ~-holomorphic curve on the punctured unit disk D∖{0}D\setminus\{0\}D∖{0}, and let 000 be a nondegenerate puncture of uuu, asymptotic to a periodic Reeb orbit PPP with sign ε\varepsilonε. Then uuu converges to the trivial cylinder over PPP exponentially fast in C∞C^\inftyC∞. If moreover π du\pi\,duπdu does not vanish identically near 000, then uuu has an asymptotic eigenvalue μ\muμ with εμ<0\varepsilon\mu<0εμ<0 and an asymptotic eigenvector of APA_PAP​ at 000 (Hryniewicz, Theorem 2.11 and Lemma 2.12).

Milestones

  1. Linearized Reeb flow. It exists, is unique, maps ξ\xiξ to ξ\xiξ preserving ω0\omega_0ω0​, and Φ(τ+T)=Φ(τ)Φ(T)\Phi(\tau+T)=\Phi(\tau)\Phi(T)Φ(τ+T)=Φ(τ)Φ(T).
  2. Isolation. Nondegenerate orbits are isolated among the orbits of the same period.
  3. Symmetry. APA_PAP​ maps ξ\xiξ-loops to ξ\xiξ-loops and is symmetric for ⟨η,ζ⟩=∫01ω0(η,Jζ) dt\langle\eta,\zeta\rangle=\int_0^1\omega_0(\eta,J\zeta)\,dt⟨η,ζ⟩=∫01​ω0​(η,Jζ)dt (Hryniewicz, Definition 2.5).
  4. Kernel. APη=0A_P\eta=0AP​η=0 if and only if η(t)=Φ(Tt)η(0)\eta(t)=\Phi(Tt)\eta(0)η(t)=Φ(Tt)η(0); so PPP is nondegenerate if and only if APA_PAP​ has trivial kernel.
  5. Unitary frames. In a unitary frame of ξ\xiξ along PPP, APA_PAP​ becomes −J0∂t−S∞(t)-J_0\partial_t-S_\infty(t)−J0​∂t​−S∞​(t) with S∞S_\inftyS∞​ symmetric, with matching nondegeneracy (Hryniewicz, Remark 2.6).
  6. Linear exponential decay. Solutions of ∂sζ+J0∂tζ+Sζ=0\partial_s\zeta+J_0\partial_t\zeta+S\zeta=0∂s​ζ+J0​∂t​ζ+Sζ=0 on a half-cylinder that tend to 000, with S→S∞S\to S_\inftyS→S∞​ in C∞C^\inftyC∞ and −J0∂t−S∞-J_0\partial_t-S_\infty−J0​∂t​−S∞​ nondegenerate, decay exponentially (Wendl, Theorem 4.6.6).
  7. Linear asymptotic formula. If S−S∞S-S_\inftyS−S∞​ decays exponentially, a nontrivial solution of at most exponential growth is eμs(e(t)+r(s,t))e^{\mu s}(e(t)+r(s,t))eμs(e(t)+r(s,t)) with eee an eigenfunction and r→0r\to0r→0 in C∞C^\inftyC∞ (Wendl, Theorem 4.8.2).
  8. No zeros at infinity for such solutions when S→S∞S\to S_\inftyS→S∞​ in C∞C^\inftyC∞ (Wendl, Corollary 4.8.3).
  9. Asymptotically cylindrical ends. If loops along one sequence of radii converge to a nondegenerate orbit, the end is asymptotically cylindrical in C∞C^\inftyC∞ (Hofer–Wysocki–Zehnder, Theorem 1.3).
  10. Exponential convergence of asymptotically cylindrical ends at nondegenerate orbits (Hryniewicz, Theorem 2.10).
  11. Zeros of π du\pi\,duπdu. At a nondegenerate puncture, if π du\pi\,duπdu does not vanish identically near the puncture, it has no zeros near it (Hryniewicz, Definition 2.9 (3)).
  12. Planes. A nonconstant finite-energy plane whose loops at ∞\infty∞ converge along one sequence to a nondegenerate orbit has exponential asymptotics and an asymptotic eigenvector there.
  13. Bridge to R4\mathbb{R}^4R4. For n=1n=1n=1, nondegeneracy agrees with the nondegeneracy condition of the HryniewiczCriterion setting.

Significance

The results. The goal is the standard description of a finite-energy end used throughout symplectic field theory: it is what makes the asymptotic eigenvalue, the winding of the asymptotic eigenvector, the asymptotic Conley–Zehnder index and the asymptotic intersection theory of punctured curves meaningful. The goal does not assume that the limit orbit is nondegenerate, only that the end decays exponentially; this hypothesis is part of the definition of fast planes over possibly degenerate orbits (Hryniewicz, Definition 2.14). Milestone 12 is the form in which planes asymptotic to nondegenerate orbits are used, and milestone 13 connects it to the open HryniewiczCriterion mission. Milestones 6–8 are results about linear Cauchy–Riemann equations on a half-cylinder, independent of the geometry.

Formalizing them. All results are classical and proved in the cited sources (the linear results in Wendl's notes and in R. Siefring, Relative asymptotic behavior of pseudoholomorphic half-cylinders, CPAM 61 (2008)). None of them has been formalized in a proof assistant, as far as a literature search shows; Mathlib has no asymptotic operators of Reeb orbits and no theory of Cauchy–Riemann equations on cylinders.

Difficulty

The asymptotic operator acts on sections of ξ\xiξ along the orbit, defined intrinsically in R2n+2\mathbb{R}^{2n+2}R2n+2 with no preferred frame, and its spectral theory lives on loops in a moving subspace. The hypothesis of the goal is only exponential C0C^0C0 convergence, while the conclusion is C∞C^\inftyC∞ convergence and a precise leading term with a single eigenvector. The eigenvector formula is stated in a tube around the orbit with its own phase function τ(s,t)\tau(s,t)τ(s,t), so the leading term is measured transversally to the orbit rather than against the parametrization x(εTt+c)x(\varepsilon Tt+c)x(εTt+c). For multiply covered orbits the tube is only a covering of a neighbourhood of the orbit, and the phase τ\tauτ is a real lift.

Formalization scope

  • Namespace FiniteEnergyPlane; the definition module FiniteEnergyPlane_Asymptotics imports FiniteEnergyPlane_Setting (previous mission) and CauchyRiemannIndex_Setting (fifth mission) for Mat n, J₀ n, Vec n, IsSymLoop, IsNondegenerate and crOp. The bridge item also imports HryniewiczCriterion_ConleyZehnder.
  • Decay on an end is stated for maps on R×R\mathbb{R}\times\mathbb{R}R×R, uniformly in ttt as s→+∞s\to+\inftys→+∞; C∞C^\inftyC∞ statements bound every iteratedFDeriv and require smoothness on some (s0,∞)×R(s_0,\infty)\times\mathbb{R}(s0​,∞)×R. Matrix-valued convergence is entrywise.
  • Eigenvectors are smooth 111-periodic ξ\xiξ-loops that are not identically zero.
  • Not included. Winding numbers of eigenvectors, the relation between the Conley–Zehnder index and windings, windπ\mathrm{wind}_\piwindπ​ and wind∞\mathrm{wind}_\inftywind∞​, fast planes, and the Morse–Bott case are left to later missions.

Contributions welcome: general lemmas on linear ODEs along periodic orbits and on smooth families of subspaces over the circle.

Selected references

  • U. Hryniewicz, Systems of global surfaces of section for dynamically convex Reeb flows on the 3-sphere, J. Symplectic Geom. 12 (2014), § 2.2.3. https://arxiv.org/abs/1105.2077
  • U. Hryniewicz, Fast finite-energy planes in symplectizations and applications, Trans. Amer. Math. Soc. 364 (2012), 1859–1931, § 3.6 and Appendix B. https://arxiv.org/abs/0812.4076
  • H. Hofer, K. Wysocki, E. Zehnder, Properties of pseudoholomorphic curves in symplectisations I: Asymptotics, Ann. Inst. H. Poincaré Anal. Non Linéaire 13 (1996), 337–379, and Correction, 15 (1998), 535–538. https://doi.org/10.1016/S0294-1449(16)30108-1
  • C. Wendl, Lectures on Symplectic Field Theory, lecture notes, Humboldt-Universität zu Berlin (2026 version), §§ 3.1, 4.6, 4.8, 6.4, 6.7; earlier version arXiv:1612.01009. https://arxiv.org/abs/1612.01009
  • R. Siefring, Relative asymptotic behavior of pseudoholomorphic half-cylinders, Comm. Pure Appl. Math. 61 (2008), Appendix A. https://arxiv.org/abs/math/0702356
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Quantum Information·Captain: Goku

Coherent Communication of Classical MessagesResearch Paper

Motivation

We define "coherent communication" in terms of a simple primitive, show it is equivalent to the ability to send a classical message with a unitary or isometric operation, and use it to relate other resources in quantum information theory. Using coherent communication, we are able to generalize super-dense coding to prepare arbitrary quantum states instead of only classical messages. We also derive single-letter formulae for the classical and quantum capacities of a bipartite unitary gate assisted by an arbitrary fixed amount of entanglement per use.

This mission is the statement-level formalization of Coherent Communication of Classical Messages (arXiv:quant-ph/0307091v3). 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 1: coherification of one-way classical communication (Proposition 1: coherification of one-way classical communication, 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

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

  • Eq. (2): displayed CNOT encoding identity: A source-defined Y or uniquely specified corrected literal identity (source-ambiguity)
  • Qualitative criterion for simultaneous coherent communication and entanglement: A quantitative, fully quantified protocol-level obliviousness hypothesis and replacement conclusion (source-ambiguity)

Selected references

  • Coherent Communication of Classical Messages, arXiv:quant-ph/0307091v3, https://arxiv.org/abs/quant-ph/0307091v3
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Quantum Information·Captain: Goku

Optimal Manipulations with Qubits: Universal NOT GateResearch Paper

Motivation

It is not a problem to complement a classical bit, i.e. to change the value of a bit, a 0 to a 1 and vice versa. This is accomplished by a NOT gate. Complementing a qubit in an unknown state, however, is another matter. We show that this operation cannot be done perfectly. We define the Universal-NOT (U-NOT) gate which out of N identically prepared pure input qubits generates M output qubits in a state which is as close as possible to the perfect complement. This gate can be realized by classical estimation and subsequent re-preparation of complements of the estimated state. Its fidelity is therefore equal to the fidelity F= (N+1)/(N+2) of optimal estimation, and does not depend on the required number of outputs. We also show that when some additional a priori information about the state of input qubit is available, than the fidelity of the quantum NOT gate can be much better than the fidelity of estimation.

This mission is the statement-level formalization of Optimal Manipulations with Qubits: Universal NOT Gate (arXiv:quant-ph/9901053v1). Every numbered result of the paper was scanned. The results stated here are open sorry goals, ready for solvers to prove.

What is formalized

12 statements of the paper are in Lean 4 (Mathlib 0df444a). The goal theorem is Optimal universal NOT error (Theorem (unnumbered), PDF p.3: optimal universal NOT error, 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

  • Optimal Manipulations with Qubits: Universal NOT Gate, arXiv:quant-ph/9901053v1, https://arxiv.org/abs/quant-ph/9901053v1
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Quantum Information·Captain: Goku

Radon-Nikodym derivatives of quantum operationsResearch Paper

Motivation

Given a completely positive (CP) map TTT, there is a theorem of the Radon-Nikodym type [W.B. Arveson, Acta Math. {\bf 123}, 141 (1969); V.P. Belavkin and P. Staszewski, Rep. Math. Phys. {\bf 24}, 49 (1986)] that completely characterizes all CP maps SSS such that T−ST-ST−S is also a CP map. This theorem is reviewed, and several alternative formulations are given along the way. We then use the Radon-Nikodym formalism to study the structure of order intervals of quantum operations, as well as a certain one-to-one correspondence between CP maps and positive operators, already fruitfully exploited in many quantum information-theoretic treatments. We also comment on how the Radon-Nikodym theorem can be used to derive norm estimates for differences of CP maps in general, and of quantum operations in particular.

This mission is the statement-level formalization of Radon-Nikodym derivatives of quantum operations (arXiv:math-ph/0303056v3). 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 Stinespring Radon–Nikodym theorem (Theorem 3.1: Stinespring Radon–Nikodym theorem (seed resolved from abstract), 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

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

  • Theorem 2.1 (Haagerup–Paulsen–Wittstock): A valid scope for the unrestricted spatial HPW factorization (source-ambiguity)
  • §2.3, unnumbered: CB norm and predual diamond norm: Compatible Banach trace-class predual, finite amplifications, trace pairing, spatial factorization cost set and attainment (hard)
  • Theorem 3.5: diagonal Kraus form as printed: A justified pure-point spectral assumption for the canonical RN derivative (source-ambiguity)
  • Theorem 5.1: uniform m^2-domination as printed: A consistent normalization for the uniform m^2 domination assertion (source-ambiguity)
  • §5.3, unnumbered: unit domination of T_omega as printed: A normalization or scale factor for the unit-domination assertion (source-ambiguity)
  • §5.3, unnumbered: regularized faithful-state reconstruction: Normal tensor amplification of CP superoperators and construction of the infinite weighted Choi operator (hard)

Selected references

  • Radon-Nikodym derivatives of quantum operations, arXiv:math-ph/0303056v3, https://arxiv.org/abs/math-ph/0303056v3
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