Manuscript Psy04-B@1 · Psy04-B-v1.tex · section · 62c2b6f0
Comparison with sequential RAC certification
Environmental memory and the required refusal › Comparison with sequential RAC certification · lines 1868–1930
Roy and colleagues study a three-party prepare-transform-measure QRAC with a quantum carrier, intermediate instruments, and a downstream receiver RoySequential. Their sharp-measurement analysis uses rank-one projective measurements at the intermediate party, and they also analyze unsharp instruments. Their classical-memory processes use environmental classical feedback, rather than making the complete processor a two-state classical system.
The relation to the present null is therefore structural: both must specify carrier dimension, complete instruments, and environmental feedback. The experimental restrictions are not identical.
distinct exclusion questions.
| Feature | Present delayed RAC | Environmental-memory task |
|---|---|---|
| Null carrier | Wholly classical, at most two states | Already quantum, dimension specified |
| Intermediate instrument | No compulsory receiver measurement | Specified and constrained |
| Retained environment | Included in the complete classical cut | Separate classical-feedback class |
| Witness meaning | Bounded classical-storage exclusion | Requires a class-specific multitime bound |
| Applicable bound | Proved here for the classical cut | Not automatically applicable |
A stronger result would require a complete-record score , a proved bound
and an admitted quantum-environment process exceeding that bound after uncertainty allowances. For arbitrary classical register size, the bound must be uniform over the admitted sizes.
No such new environmental optimization or certificate is claimed here. Linear dependence of a fixed witness on a process representation does not automatically make a joint optimization over processes and instruments convex.
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