Probing the <u>Tavis</u>-Cummings level splitting with intermediate-scale superconducting circuits

ORAL

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, being 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 is limited by reduced signal visibility, and -if uncalibrated- by off-resonance shifts of sub-components. Our work demonstrates control and readout of quantum coherent mesoscopic multi-qubit system of intermediate scale under conditions of noise.

*China Scholarship Council (CSC), European Research Council (ERC-648011), DFG project INST 121384/138-1 FUGG, Helmholtz IVF 'Scalable solid state quantum computing'

Presenters

  • Martin Weides

    • School of Engineering, University of Glasgow
    • University of Glasgow

Authors

  • Martin Weides

    • School of Engineering, University of Glasgow
    • University of Glasgow
  • Ping Yang

    • Institute of Physics, Karlsruhe Institute of Technology
  • Jan David Brehm

    • Institute of Physics, Karlsruhe Institute of Technology
  • Juha Leppaekangas

    • Karlsruher Institut für Technologie
    • Institute of Physics, Karlsruhe Institute of Technology
  • Lingzhen Guo

    • Max Planck Institute for the Physics of Light
    • Max Planck Institute for the Science of Light
  • Michael Marthaler

    • Theoretische Physik, Saarland University
    • Institute for Theoretical Condensed Matter physics, Karlsruhe Institute of Technology
  • Isabella Boventer

    • Institute of Physics, University Mainz
  • Alexander Stehli

    • Institute of Physics, Karlsruhe Institute of Technology
  • Tim Wolz

    • Institute of Physics, Karlsruhe Institute of Technology
  • Alexey Ustinov

    • Karlsruhe Institute of Technology
    • Institute of Physics, Karlsruhe Institute of Technology