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

\[E(\mathcal{E}, U) = 1 - F_{\text{ave}}(\mathcal{E}, U)\]

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 \(Tr_{\mbox{out}}[\mathcal{E}] - I\) [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.