qat.quops.metrics.get_process_distance

qat.quops.metrics.get_process_distance(chan1, chan2=None)

Compute the process distance between two channels

\[D{\mathrm{pro}}(\mathcal{E},\mathcal{F})=D(\rho_{\mathcal{E}},\rho_{\mathcal{F}})\]

with \(D\) the trace distance (defined in get_trace_distance()), and \(\rho_\mathcal{E}\) the Choi-Jamiolkowski representation of the channel.

Parameters

chan1 (QuantumChannel[PTM|Kraus|Choi]) – the first channel \(\mathcal{E}\)
chan2 (QuantumChannel[PTM|Kraus|Choi], optional) – the second channel \(\mathcal{F}\). Defaults to None (identity).

Returns

the process distance

Return type

float