qiskit.quantum_info.average_gate_fidelity

average_gate_fidelity(channel, target=None, require_cp=True, require_tp=False)

Return the average gate fidelity of a noisy quantum channel.

The average gate fidelity $F_{\text{ave}}$ is given by

where $F_{\text{pro}}(\mathcal{E}, U)$ is the process_fidelity() of the input quantum channel $\mathcal{E}$ with a target unitary $U$, and $d$ is the dimension of the channel.

Parameters

• channel (QuantumChannel or Operator) – noisy quantum channel.
• target (Operator or None) – target unitary operator. If None target is the identity operator [Default: None].
• require_cp (bool) – check if input and target channels are completely-positive and if non-CP log warning containing negative eigenvalues of Choi-matrix [Default: True].
• require_tp (bool) – check if input and target channels are trace-preserving and if non-TP log warning containing negative eigenvalues of partial Choi-matrix $Tr_{\text{out}}[\mathcal{E}] - I$ [Default: True].

Returns

The average gate fidelity $F_{\text{ave}}$.

Return type

float

Raises

QiskitError – if the channel and target do not have the same dimensions, or have different input and output dimensions.