FA-91254 / Quantum circuit simulation / Member archive

Dephasing uses 1-p instead of 1-2p · case 04

A phase-flip probability of 0.5 leaves half the coherence instead of erasing it.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

Input [[x, y, z], channels] (decimal strings). Apply in order: depol p (r -> (1-p) r), dephase p (x, y scaled by 1-2p), bitflip p (y, z scaled by 1-2p), ampdamp g (x, y scaled by sqrt(1-g), z -> g + (1-g) z toward |0> at z=+1), h ((x,y,z) -> (z,-y,x)), s ((x,y) -> (-y,x)), x ((y,z) -> (-y,-z)). Return the final vector rounded to 6 decimals.

Why this case matters

Single-qubit noise channels on the Bloch ball are the standard sanity model for T1/T2 behaviour; axis or scale slips mislead calibration.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression: random channel chain 19	`[0.311678, -0.112497, 0.301862]`	`[0.295274, -0.106576, 0.301862]`	Failed

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