Dynamics of superconducting qubit relaxation times

By Malcolm Carroll, S. Rosenblatt, P. Jurcevic, I. Lauer, Abhinav Kandala. npj Quantum Information, 2021

132 citations recorded by the source corpus.

Superconducting qubits are a leading candidate for quantum computing but display temporal fluctuations in their energy relaxation times T 1 . This introduces instabilities in multi-qubit device performance. Furthermore, autocorrelation in these time fluctuations introduces challenges for obtaining representative measures of T 1 for process optimization and device screening. These T 1 fluctuations are often attributed to time varying coupling of the qubit to defects, putative two level systems (TLSs). In this work, we develop a technique to probe the spectral and temporal dynamics of T 1 in single junction transmons by repeated T 1 measurements in the frequency vicinity of the bare qubit transition, via the AC-Stark effect. Across 10 qubits, we observe strong correlations between the mean T 1 averaged over approximately nine months and a snapshot of an equally weighted T 1 average over the Stark shifted frequency range. These observations are suggestive of an ergodic-like spectral diffusion of TLSs dominating T 1 , and offer a promising path to more rapid T 1 characterization for device screening and process optimization.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/d03a75a18914b241f26240ea048469d5ba409e31

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In Artificial Intelligence

In Atomic and Molecular Physics, and Optics

Citations in the corpus

Probabilistic error cancellation with sparse Pauli–Lindblad models on noisy quantum processors (2022, background): “As typical for supercomputing qubits [48, 49], these times ﬂuctuated over the duration of the experiments.”