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) – require channel to be completely-positive [Default: True].
• require_tp (bool) – require channel to be trace-preserving [Default: False].

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.
• QiskitError – if the channel and target or are not completely-positive (with require_cp=True) or not trace-preserving (with require_tp=True).