Interacting two-level defects as sources of fluctuating high-frequency noise in superconducting circuits

By C. Muller, J. Lisenfeld, A. Shnirman, S. Poletto. 2015

139 citations recorded by the source corpus.

Since the very first experiments, superconducting circuits have suffered from strong coupling to environmental noise, destroying quantum coherence and degrading performance. In state-of-the-art experiments, it is found that the relaxation time of superconducting qubits fluctuates as a function of time. We present measurements of such fluctuations in a 3D-transmon circuit and develop a qualitative model based on interactions within a bath of background two-level systems (TLS) which emerge from defects in the device material. In our model, the time-dependent noise density acting on the qubit emerges from its near-resonant coupling to high-frequency TLS which experience energy fluctuations due to their interaction with thermally fluctuating TLS at low frequencies. We support the model by providing experimental evidence of such energy fluctuations observed in a single TLS in a phase qubit circuit.

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

View Paper: https://www.semanticscholar.org/paper/a789331ea9acd76ec1aac780d8ae2d625a4ac3de

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In Artificial Intelligence

In Atomic and Molecular Physics, and Optics

Citations in the corpus

Leakage reduction in fast superconducting qubit gates via optimal control (2020, background): “Effects that are hard to accurately reproduce in simulation include instrument noise, transfer functions [23–25], additional modes and coupling to unwanted quantum systems [26].”
Error mitigation extends the computational reach of a noisy quantum processor (2018, methodology): “Also, for superconducting qubits, that often show fluctuations [16] in relaxation T1 and coherence times T2, the requirement of time-translation invariant noise implies that the measurements under the scaled dynamics need to be made within the typical timescales of these fluctuations (see supplement”