Observation of discrete charge states of a coherent two-level system in a superconducting qubit

• URL: http://arxiv.org/abs/2401.12183v2
• Date: Mon, 18 Mar 2024 16:42:27 GMT
• Title: Observation of discrete charge states of a coherent two-level system in a superconducting qubit
• Authors: Bao-Jie Liu, Ying-Ying Wang, Tal Sheffer, Chen Wang,
• Abstract summary: We report observations of discrete charge states of a coherent two-level system (TLS) that is strongly coupled to an offset-charge-sensitive superconducting transmon qubit. We measure an offset charge of 0.072$e$ associated with the two TLS eigenstates, which have a transition frequency of 2.9 GHz and a relaxation time exceeding 3 ms. This study demonstrates microwave-frequency TLS as a source of low-frequency charge noise.
• Score: 7.741509997023564
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We report observations of discrete charge states of a coherent dielectric two-level system (TLS) that is strongly coupled to an offset-charge-sensitive superconducting transmon qubit. We measure an offset charge of 0.072$e$ associated with the two TLS eigenstates, which have a transition frequency of 2.9 GHz and a relaxation time exceeding 3 ms. Combining measurements in the strong dispersive and resonant regime, we quantify both transverse and longitudinal couplings of the TLS-qubit interaction. We further perform joint tracking of TLS transitions and quasiparticle tunneling dynamics but find no intrinsic correlations. This study demonstrates microwave-frequency TLS as a source of low-frequency charge noise.

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