Round 2 verification audit for C058

Model: gpt-5

Claim: For the protocol the fidelity with |Psi^-> is extracted after 80 cycles, while for the comparison single-loop (length t) and two-loop (length t sqrt(2)) MS gates the fidelity is taken against (|down,down> - i|ee>)/sqrt(2).

Source alignment: source/supp_content.tex:100-101 (Supp. Mat. S3)

Prior official verdict: partial with failure_reason None.

Executable evidence: run.py. Sandbox rerun logs: run.log.

Independent audit: I scanned the copied script for imports/shared helper dependencies and reran it through the sandbox. The code is self-contained in this attempt directory and targets the claim strategy: Confirm the simulation protocol: 80 cycles for the dissipative scheme and the stated MS-gate lengths and target states.. I checked the relevant family model rather than relying only on exit status; the rerun is treated as one reproducibility input.

Decision: Round 2 verdict is partial with failure_reason None and limitations ['paper_text_only_reimplementation']. Notes: Descriptive simulation-protocol claim corroborated structurally with the self-contained model. MS gate from H_A reaches the triplet Bell target (|dd>-i|ee>)/sqrt2 (fidelity 1.0); protocol steady state is |Psi-> (F=1) and 80 cycles converges (F=0.99998 from |dd>, N0=7.62 so 80 = 10.5 N0), confirming 80 cycles is a sensible fidelity-extraction point. Single-loop (length t) vs two-loop (length t*sqrt2) are path/duration descriptors of the same net area. This is a descriptive protocol choice, not a reproduced measurement, so capped at partial.