fiqci.ems.transpiler_passes.basis_measurement

Functions

get_obs_subcircuits(subcircuits, ...[, ops])

Generate modified subcircuits for each measurement setting by applying the _ModifyMeasurementBasis transpiler pass.

Classes

ModifyMeasurementBasis(*args, **kwargs)

A transpiler pass that modifies the measurement basis of a circuit according to specified settings.

class ModifyMeasurementBasis(*args, **kwargs)

Bases: TransformationPass

A transpiler pass that modifies the measurement basis of a circuit according to specified settings. It adds the necessary gates to change the measurement basis to X or Y as needed, and appends measurements in the Z basis. This allows for flexible measurement settings to be applied to circuits before execution, enabling the calculation of expectation values for different observables without needing to manually modify the circuits.

Parameters:

• measurement_settings – A list of dictionaries, where each dictionary maps qubit indices to measurement bases (“X”, “Y”, or “Z”). Each dictionary represents a different measurement setting to apply to the circuit.

• ops – An optional dictionary mapping measurement basis labels (e.g., “X-meas”, “Y-meas”) to custom Instruction objects that implement the necessary basis change. If provided, these custom instructions will be used instead of the default H and Sdg+H gates for X and Y basis changes, respectively.

__init__(measurement_settings: list[dict[int, str]], ops: dict[str, Instruction] | None = None)

run(dag: DAGCircuit) → DAGCircuit

Run a pass on the DAGCircuit. This is implemented by the pass developer.

Parameters:

dag – the dag on which the pass is run.

Raises:

NotImplementedError – when this is left unimplemented for a pass.

get_obs_subcircuits(subcircuits: list[QuantumCircuit], measurement_settings: list[dict[int, str]], ops: dict[str, Instruction] | None = None) → list[dict[int, QuantumCircuit]]

Generate modified subcircuits for each measurement setting by applying the _ModifyMeasurementBasis transpiler pass. This function takes a list of subcircuits and a list of measurement settings, and returns a list of dictionaries mapping circuit indices to their corresponding modified subcircuits for each measurement setting.

TODO: pass observables direclty to this function and determine measerement_settings here. Easier manual use if desired and cleaner code.

Parameters:

• subcircuits – A list of QuantumCircuit objects.

• measurement_settings – A list of dictionaries mapping qubit indices to measurement bases.

• ops – An optional dictionary mapping measurement basis labels to custom Instruction objects.

Returns:

A list of dictionaries mapping circuit indices to their corresponding modified subcircuits for each measurement setting.