FA-90864 / Quantum circuit simulation / Member archive

Statevector T gate uses the pi/8 name as its phase · case 04

After H then T the |1> amplitude has phase 22.5 degrees instead of 45 degrees.

Member previewVariant 4 · 3 implementations · 6 checks per implementation

Case contract

Input [n, gates]; start in |0...0>, apply gates h,x,y,z,s,sdg,t (["g", q]) and cx,cz,swap (["g", a, b]) with qubit 0 as the least significant bit of the basis index; return the statevector as [re, im] pairs rounded to 6 decimals.

Why this case matters

Statevector simulators underpin circuit unit tests; a gate-kernel slip silently corrupts every downstream amplitude.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression: random circuit 29	`[[0.5, 0.0], [-0.46194, -0.191342], [0.0, 0.5], [-0.191342, 0.46194]]`	`[[0.5, 0.0], [-0.353553, -0.353553], [0.0, 0.5], [-0.353553, 0.353553]]`	Failed

MEMBER ARCHIVE

The complete case is available to members.

This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

Member access is invitation-based. Sign in with your invited account to inspect the sources.