Probing the Tavis-Cummings level splitting with intermediate-scale superconducting circuits

Yang, P., Brehm, J. D., Leppäkangas, J., Guo, L., Marthaler, M., Boventer, I., Stehli, A., Wolz, T., Ustinov, A. V. and Weides, M. (2020) Probing the Tavis-Cummings level splitting with intermediate-scale superconducting circuits. Physical Review Applied, 14(2), 024025. (doi: 10.1103/PhysRevApplied.14.024025)

Abstract

We demonstrate the local control of up to eight two-level systems interacting strongly with a microwave cavity. Following calibration, the frequency of each individual two-level system (qubit) is tunable without influencing the others. Bringing the qubits one by one on resonance with the cavity, we observe the collective coupling strength of the qubit ensemble. The splitting scales up with the square root of the number of the qubits, which is the hallmark of the Tavis-Cummings model. The local control circuitry causes a bypass shunting the resonator, and a Fano interference in the microwave readout, whose contribution can be calibrated away to recover the pure cavity spectrum. The simulator’s attainable size of dressed states with up to five qubits is limited by reduced signal visibility, and—if uncalibrated—by off-resonance shifts of subcomponents. Our work demonstrates control and readout of a quantum coherent mesoscopic multiqubit system of intermediate scale under conditions of noise.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Weides, Professor Martin
• Authors: Yang, P., Brehm, J. D., Leppäkangas, J., Guo, L., Marthaler, M., Boventer, I., Stehli, A., Wolz, T., Ustinov, A. V., and Weides, M.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Physical Review Applied
• Publisher: American Physical Society
• ISSN: 2331-7019
• ISSN (Online): 2331-7019
• Published Online: 11 August 2020
• Copyright Holders: Copyright © 2020 American Physical Society
• First Published: First published in Physical Review Applied 14(2): 024025
• Publisher Policy: Reproduced in accordance with the publisher copyright policy

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