C055 - The steady-state error caused by residual spin-motion entanglement is found in simulation...
Verdict: partial
Location: Supp. Mat. S2
Type / expected artifact: empirical / math / numeric
Claim: The steady-state error caused by residual spin-motion entanglement is found in simulation to be almost identical to that introduced by U_x(sqrt(2 p)), so the main-text simulations apply to both error sources.
Models: extraction claude-opus-4-8; verification gpt-5; verification_chain claude-opus-4-8 -> gpt-5; verdict_chain partial -> partial.
Limitations: paper_text_only_reimplementation.
Source location(s): source/supp_content.tex:84 (Supp. Mat. S2).
Conclusion
Claim (supp S2): steady-state error from residual spin-motion entanglement is almost identical to that from U_x(sqrt(2p)). Reimplemented both: (A) unitary U_x(eps); (B) state-dependent residual displacement V=exp[(alpha a^dag - alpha a)(x)S_x] on spin(x)truncated oscillator (NFOCK=16, CPTP verified), motion traced out. Calibrated eps and alpha to the SAME operational p (single-event one-flip probability from |dn,dn>, supp l.82-84). Matched-p steady-state errors 1-F: p=0.005 1.57e-2 vs 1.57e-2 (0.5%); 0.01 3.09e-2 vs 3.12e-2 (1.0%); 0.02 6.01e-2 vs 6.13e-2 (2.0%); 0.04 (4.0%); 0.06 (6.1%). Max rel diff 6.1%, <1% at small p. Almost identical, as claimed. Also confirmed paper's eps=sqrt(2p) (operational p_A~0.0099 at eps=sqrt(20.01)). Requires reimplemented motional model + Fock truncation => partial.
Verification details
Executable rerun: run.py exited 0 in 1.083s; log verification/C055/attempts/R002/run.log.
Output excerpt:
NFOCK=16 params Phi=0.7854 gamma=0.6943 theta=2.2494
check model-A: at eps=sqrt(2p), p=0.01: operational p_A=0.00993
check model-A: at eps=sqrt(2p), p=0.02: operational p_A=0.01973
p(target) eps_A alpha_B 1-F (U_x) 1-F (spin-mot) rel.diff
0.0050 0.1002 0.0503 1.566437e-02 1.574266e-02 4.998e-03
0.0100 0.1419 0.0714 3.088845e-02 3.119715e-02 9.994e-03
0.0200 0.2014 0.1021 6.009273e-02 6.129441e-02 2.000e-02
0.0400 0.2868 0.1476 1.140064e-01 1.185849e-01 4.016e-02
0.0600 0.3537 0.1852 1.627131e-01 1.725995e-01 6.076e-02
max pointwise relative difference (matched operational p) = 6.076e-02