arXiv:2207.01740 · Physical Review Applied

Characterizing Low-Frequency Qubit Noise

Filip Wudarski, Yaxing Zhang, Alexander N. Korotkov, A. G. Petukhov, M. I. Dykman

Published Jun 22, 2023• 15 citations

Abstract

Fluctuations of the qubit frequencies are one of the major problems to overcome on the way to scalable quantum computers. Of particular importance are fluctuations with a correlation time that exceeds the decoherence time due to decay and dephasing by fast processes. The statistics of the fluctuations can be characterized by measuring the correlators of the outcomes of periodically repeated Ramsey measurements. We describe qubit dynamics during repeated measurements and evaluate the two-time correlator for noise from two-level systems and two- and three-time correlators for Gaussian noise. The explicit expressions for the correlators are compared with simulations. We find that, even though the three-time correlators for noise from two-level systems and for Gaussian noise are generally significantly different, already ten two-level systems can mimic Gaussian noise provided they are symmetric. This is not the case for asymmetric systems.

DOI: 10.1103/physrevapplied.19.064066

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