qiskit.quantum_info.gate_error

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

Return the gate error of a noisy quantum channel.

The gate error $E$ is given by the average gate infidelity

where $F_{\text{ave}}(\mathcal{E}, U)$ is the average_gate_fidelity() of the input quantum channel $\mathcal{E}$ with a target unitary $U$.

Parameters

• channel (QuantumChannel) – 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 error $E$.

Return type

float

Raises

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