BaseStateFidelity

class BaseStateFidelity(*, transpiler=None, transpiler_options=None)[source]

Bases: ABC

An interface to calculate state fidelities (state overlaps) for pairs of (parametrized) quantum circuits. The calculation depends on the particular fidelity method implementation, but can be always defined as the state overlap:

\[|\langle\psi(x)|\phi(y)\rangle|^2\]

where \(x\) and \(y\) are optional parametrizations of the states \(\psi\) and \(\phi\) prepared by the circuits circuit_1 and circuit_2, respectively.

Parameters:

  • transpiler (Transpiler | None) – An optional object with a run method allowing to transpile the circuits that are produced within this algorithm. If set to None, these won’t be transpiled.

  • transpiler_options (dict[str, Any] | None) – A dictionary of options to be passed to the transpiler’s run method as keyword arguments.

Methods

abstract create_fidelity_circuit(circuit_1, circuit_2)[source]

Implementation-dependent method to create a fidelity circuit from 2 circuit inputs.

Parameters:
Returns:

The fidelity quantum circuit corresponding to circuit_1 and circuit_2.

Return type:

QuantumCircuit

run(circuits_1, circuits_2, values_1=None, values_2=None, *, shots=None)[source]

Runs asynchronously the state overlap (fidelity) calculation between two (parametrized) circuits (first and second) for a specific set of parameter values (first and second). This calculation depends on the particular fidelity method implementation.

Parameters:

  • circuits_1 (QuantumCircuit | Sequence[QuantumCircuit]) – (Parametrized) quantum circuits preparing \(|\psi\rangle\).

  • circuits_2 (QuantumCircuit | Sequence[QuantumCircuit]) – (Parametrized) quantum circuits preparing \(|\phi\rangle\).

  • values_1 (Sequence[float] | Sequence[Sequence[float]] | None) – Numerical parameters to be bound to the first set of circuits.

  • values_2 (Sequence[float] | Sequence[Sequence[float]] | None) – Numerical parameters to be bound to the second set of circuits.

  • shots (int | Sequence[int] | None) – Number of shots to be used by the underlying sampler. If a single integer is provided, this number will be used for all circuits. If a sequence of integers is provided, they will be used on a per-circuit basis. If none is provided, the fidelity’s default number of shots will be used for all circuits. If this number is also set to None, the underlying primitive’s default number of shots will be used for all circuits.

Returns:

Primitive job for the fidelity calculation. The job’s result is an instance of StateFidelityResult.

Return type:

AlgorithmJob