Coherent control of two qubits in coaxial circuit QED

ORAL

Abstract

We demonstrate the extension of a coaxial circuit QED architecture [1] to two qubits, including tune up of two-qubit quantum logic gates based on the cross-resonance interaction [2].

A major obstacle in scaling up monolithic superconducting-circuit quantum computing architectures is the circuit complexity that results from integration of the required control and measurement lines with the qubits. We address this obstacle by adopting a circuit architecture with entirely off-chip out-of-plane wiring; coaxial qubits ("coaxmons") and lumped element LC resonators are fabricated on opposing sides of a single chip, and control and readout are provided by coaxial cables running perpendicular to the chip plane.

We present the first measurements of pairs of detuned, weakly capacitively coupled, static frequency coaxmon qubits. The cross-resonance interaction between the qubits is characterised using process tomography, and the results are used to tune the microwave drives applied to the two qubits to optimise gate fidelities.

*We acknowledge financial support from the EPSRC under grant EP/M013243/1, and Oxford Instruments Nanoscience.

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Presenters

  • Andrew Patterson

    • Physics, University of Oxford
    • Condensed Matter Physics, University of Oxford
    • Clarendon Laboratory, University of Oxford

Authors

  • Andrew Patterson

    • Physics, University of Oxford
    • Condensed Matter Physics, University of Oxford
    • Clarendon Laboratory, University of Oxford

  • Joseph Rahamim

    • Physics, University of Oxford
    • Condensed Matter Physics, University of Oxford
    • Clarendon Laboratory, University of Oxford

  • Takahiro Tsunoda

    • Condensed Matter Physics, University of Oxford

  • Peter Spring

    • Condensed Matter Physics, University of Oxford

  • Tanja Behrle

    • Condensed Matter Physics, University of Oxford
    • Clarendon Laboratory, University of Oxford

  • Martina Esposito

    • Condensed Matter Physics, University of Oxford

  • Giovanna Tancredi

    • Physics, University of Oxford
    • Condensed Matter Physics, University of Oxford
    • Clarendon Laboratory, University of Oxford

  • Peter Leek

    • Physics, University of Oxford
    • Clarendon Laboratory, Department of Physics, University of Oxford
    • Condensed Matter Physics, University of Oxford
    • Clarendon Laboratory, University of Oxford