quchip.engine.monitoring¶
Select declared physical channels for continuous diffusive monitoring.
Functions
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Lower physical couplings once, keeping selected channel order and phases. |
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Return a diffusive request monitoring selected declared channels. |
- quchip.engine.monitoring.with_monitoring(problem, efficiencies, *, phases=None)[source]¶
Return a diffusive request monitoring selected declared channels.
- Parameters:
problem (SolveProblem or SolveBatch) – Captured diffusive solve request or parameter batch.
efficiencies (mapping) – Resolved channel key or SLHChannel to efficiency in [0, 1]. Unlisted channels remain unobserved. Inspect
problem.engine_result.slh.channels.phases (mapping or None, default None) – Channel key or SLHChannel to homodyne phase in radians, relative to the captured integration frame. Omitted phases are zero. Channel coupling phases are kept. This does not model downstream receiver processing.
- Returns:
Captured selection. For pure-state SSE, all losses must be monitored with unit efficiency. Native SME owns inefficient state evolution. After an elimination, a solve rejects a positive efficiency on a channel that carries the emission of a retained multiport mode response, because time-domain dynamics omit its pole. This includes a hidden channel that acted on the removed mode. A traced efficiency counts as positive.
- Return type:
Notes
QuTiP uses S = sqrt(eta) exp(-i phase) L and C = sqrt(1-eta) L, preserving D[S] + D[C] = D[L]. Dynamiqs receives L and eta directly. See Wiseman and Milburn, Quantum Measurement and Control, chapter 4 (https://doi.org/10.1017/CBO9780511813948).