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Pauli expectation omits complex conjugation of the bra · case 02

Complex states return expectations that differ from <psi|P|psi>, e.g. <X> on |+i> is nonzero.

Member previewVariant 2 · 3 implementations · 7 checks per implementation

Case contract

Input [n, amps, pauli]; pauli is an n-character string over I,X,Y,Z whose rightmost character acts on qubit 0 (LSB). Return the real expectation <psi|P|psi>/<psi|psi> rounded to 6 decimals. Errors: "length-mismatch", "bad-pauli" (any character outside uppercase IXYZ).

Why this case matters

Pauli expectation values are the observable layer of variational algorithms; string-order or phase slips bias every energy estimate.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression: random expectation 2	`-0.523769`	`-0.200793`	Failed

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