Characterisation of spatial charge sensitivity in a multi-mode superconducting qubit

• URL: http://arxiv.org/abs/2108.02105v1
• Date: Wed, 4 Aug 2021 15:12:56 GMT
• Title: Characterisation of spatial charge sensitivity in a multi-mode superconducting qubit
• Authors: J. Wills, G. Campanaro, S. Cao, S. D. Fasciati, P. J. Leek, B. Vlastakis
• Abstract summary: In superconducting qubits, low frequency charge noise is a well-known decoherence mechanism that is effectively suppressed in the transmon qubit. Here we characterise charge-sensitivity in a superconducting qubit with two transmon-like modes, each of which is sensitive to multiple charge-parity configurations and charge-offset biases. We provide a predictive theory for charge sensitivity in such multi-mode qubits which agrees with our results.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Understanding and suppressing sources of decoherence is a leading challenge in building practical quantum computers. In superconducting qubits, low frequency charge noise is a well-known decoherence mechanism that is effectively suppressed in the transmon qubit. Devices with multiple charge-sensitive modes can exhibit more complex behaviours, which can be exploited to study charge fluctuations in superconducting qubits. Here we characterise charge-sensitivity in a superconducting qubit with two transmon-like modes, each of which is sensitive to multiple charge-parity configurations and charge-offset biases. Using Ramsey interferometry, we observe sensitivity to four charge-parity configurations and track two independent charge-offset drifts over hour timescales. We provide a predictive theory for charge sensitivity in such multi-mode qubits which agrees with our results. Finally, we demonstrate the utility of a multi-mode qubit as a charge detector by spatially tracking local-charge drift.

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