Round 2 verification audit for C018

Model: gpt-5

Claim: In the absence of other errors, the protocol produces |Psi^-> regardless of the ions' temperature.

Source alignment: source/main.tex:122-122 (Experiment)

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 by simulation that the cycle superoperator's steady state remains |Psi^-> independent of initial motional occupation when no local errors are present.. 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: Claim: error-free protocol produces |Psi^-> regardless of temperature. the self-contained model is spin-only (no motional dof), so temperature is checkable only structurally: the error-free cycle has a UNIQUE fixed point |Psi^-> (F=1.0 exactly; 2nd-eigenvalue magnitude 0.877<1). Iterating from pure states (|dn,dn>,|up,up>,|Psi^+>), the maximally-mixed = infinite-T state, and random mixed states all converge to |Psi^-> (min F=0.99999983 after 120 cycles; residual is just the 0.877^120 transient). Temperature enters the physical system only as initial motional condition / temperature-dependent LOCAL errors, which are absent here, so the fixed point is temperature-independent. Structural/initial-condition content confirmed; full temperature claim is a paper-text argument (no motional dof). Capped at partial.