AxQM: A Textbook-Scale Benchmark for Formal Proof Synthesis in a Library of Finite-Dimensional Quantum Mechanics
Weichen Winston Yin, Jacob M. Taylor, Dirk R. Englund, Frank H. L. Koppens
quant-ph
Sep 4, 2026 · v1
cs.AI cs.LO
TL;DR
Releases AxQM, 1,019 kernel-checkable Lean proof-synthesis tasks over a custom finite-dimensional quantum mechanics library forked from Mathlib.
Abstract
Formalizing mathematics in a proof assistant, where a machine checks every definition, statement and proof, has set a new standard of rigor. Large language models are now capable of formalizing autonomously, even at the scale of whole textbooks. We bring this standard of rigor to physics, where theoretical arguments carry idealizations that are rarely stated fully, and any logical gaps could have a cascading effect on interdependent results. Recognizing the need to evaluate autoformalization systems for physics, we release AxQM, 1,019 kernel-checkable proof-synthesis tasks over 479 items drawn from the textbook Quantum Computation and Quantum Information by Nielsen and Chuang. The tasks are stated in a custom Lean library of finite-dimensional quantum mechanics. By task count, it is the largest proof-synthesis benchmark in physics by a factor of four. AxQM is derived from a near-complete formalization of the formal portions of the textbook, so every task is guaranteed a solution, which we keep private. Grading of the benchmark is done deterministically by the Lean kernel, which checks that the proof compiles, that no sorry appears in it or in any declaration it depends on, and that it introduces no new axioms.
Problem
Autoformalization systems for physics lack rigorous, machine-checkable benchmarks. Physical reasoning carries unstated idealizations whose logical gaps can propagate through interdependent results.
Approach
A near-complete Lean formalization of the formal portions of Nielsen and Chuang's Quantum Computation and Quantum Information is built on a custom finite-dimensional quantum mechanics library. From it, 1,019 proof-synthesis tasks over 479 items are derived, each a formal Lean statement with a private guaranteed reference proof. The library uses a Mathlib fork that generalizes MultilinearMap to a multi-semilinear map for defining inner products on tensor powers. Grading is deterministic via the Lean kernel, checking compilation, absence of sorry, and no new axioms.
Results
AxQM contains 1,019 tasks spanning difficulty from one-line Pauli identities to proofs requiring 450+ declarations beyond the library. It is described as the largest proof-synthesis benchmark in physics by task count by a factor of four.
| Proof length estimate | Tasks | Share |
|---|
| very small | 158 | 15.5% |
| small | 324 | 31.8% |
| moderate | 280 | 27.5% |
| large | 190 | 18.6% |
| very large | 67 | 6.6% |
Proof length estimates for the 1,019 benchmark tasks