ParityHandle#

class ParityHandle(instruction)[source]#

A lightweight handle representing the result of a parity computation in quantum circuits.

ParityHandle objects are returned by qrisp.QuantumCircuit.parity() and serve as keys in the detector and observable maps produced by to_stim(). They enable tracking of parity check results throughout circuit manipulation pipelines.

Attributes:

instructionInstruction: The Instruction object containing the ParityOperation that sits in the circuit’s data list (qc.data).
clbitslist[Clbit]: Get the clbits involved in this parity from the underlying instruction.
expectationint: Get the expected parity value from the underlying instruction.
observablebool: Get whether this parity is an observable from the underlying instruction.

Examples

ParityHandles are typically created via qrisp.QuantumCircuit.parity():

>>> from qrisp import QuantumCircuit
>>> qc = QuantumCircuit(2, 2)
>>> qc.h(0)
>>> qc.cx(0, 1)
>>> qc.measure([0, 1], [0, 1])
>>> handle = qc.parity([qc.clbits[0], qc.clbits[1]], expectation=0)
>>> handle.clbits
[Clbit(cb_2), Clbit(cb_3)]
>>> handle.expectation
0

Use handles as keys in Stim conversion maps:

>>> stim_circuit, meas_map, det_map = qc.to_stim(
...     return_measurement_map=True,
...     return_detector_map=True
... )
>>> det_map[handle]  # Get the Stim detector index
0