|View source on GitHub|
Logarithmic XEB fidelity estimator.
cirq.experiments.log_xeb_fidelity_from_probabilities( hilbert_space_dimension: int, probabilities: Sequence[float] ) -> float
Estimates fidelity from ideal probabilities of observed bitstrings.
linear_xeb_fidelity_from_probabilities for the assumptions made
by this estimator.
The mean of this estimator is the true fidelity f and the variance is
(pi^2/6 - f^2) / M
where f is the fidelity and M the number of observations, equal to len(probabilities). This is better than linear XEB (see above) when fidelity is f > 0.32. Since this estimator is unbiased, the variance is equal to the mean squared error of the estimator.
The estimator is intended for use with xeb_fidelity() below.
||Dimension of the Hilbert space on which the channel whose fidelity is being estimated is defined.|
||Ideal probabilities of bitstrings observed in experiment.|
|Estimate of fidelity associated with an experimental realization of a quantum circuit.|