Measurement in Pauli-Y basis leaves qubit in incorrect state #48
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swernli
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Mar 14, 2023
This change fixes measurement in the Pauli-Y basis by resolving a but in how basis changes are unmapped after a call to `__quantum__qis__measure__body`. It also introduces a scenario test that verifies the behavior of Pauli-Y measurement using basis changes, assertions, and repeated measurement. Fixes Measurement in Pauli-Y basis leaves qubit in incorrect state #48.
swernli
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Mar 15, 2023
* Fix `unmap_pauli` for Pauli-Y measurement This change fixes measurement in the Pauli-Y basis by resolving a but in how basis changes are unmapped after a call to `__quantum__qis__measure__body`. It also introduces a scenario test that verifies the behavior of Pauli-Y measurement using basis changes, assertions, and repeated measurement. Fixes Measurement in Pauli-Y basis leaves qubit in incorrect state #48. * Convert test from bitcode to Rust * Add comments to test * Make tests more focused/unit
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Currently the implementation of
__quantum__qis__measure__bodyuses themap_paulisandunmap_paulishelper functions to handle switching between the given Pauli basis and the computational basis. However, the Pauli-Y case for those helpers is identitcal (HSH) when really theunmap_paulishould use the adjoint, (HSdgH). This is a simple one line fix, but is missing an adequate test case that would be somewhat complex (verifying not only that the measurement is correct but that subsequent operations are consistent with the measured state). One potential course for verifying the unmapping happens correctly would be repeated measurement, but testing would be needed to confirm that this detects the issue.The text was updated successfully, but these errors were encountered: