arXiv:2010.11498 · Physical Review A

Randomized benchmarking in the presence of time-correlated dephasing noise

Jiaan Qi, Hui Khoon Ng

Published Feb 15, 2021• 8 citations

Abstract

Randomized benchmarking (RB) has emerged as a popular and easy-to-implement experimental technique for gauging the quality of gate operations in quantum computing devices. A typical randomized benchmarking procedure identifies the exponential decay in the fidelity as the benchmarking sequence of gates increases in length, and the decay rate is used to estimate the fidelity of the gate. Our current theory of RB, based on the assumption of time-independent or static noise in the gates, predicts an exponential decay in the fidelity. Observed deviations from the standard exponential decay are usually attributed to some amount of time correlations in the noise, though the precise mechanisms for deviation have yet to be fully explored. In this paper, we examine this question of randomized benchmarking for time-correlated noise---specifically for time-correlated dephasing noise for exact solvability---and elucidate the circumstances in which a deviation from exponential decay can be expected, as well as point out situations where exponential decay prevails despite the presence of time correlations.

DOI: 10.1103/physreva.103.022607

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