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Automatic Two-qubit Gate Calibration with QubiC

ORAL

Abstract

Two-qubit gate calibration is a complex and time-consuming task. We developed an efficient and systematic method to automatically tune up a CNOT gate with QubiC - a customized FPGA-based Qubit Control system at LBNL. The native cross-resonance (CR) gate time and amplitude were identified by stacking multiple CR pulses. We applied a virtual Z gate on a degenerate prepared state, followed by an X90 gate. By scanning the Z gate phase, we projected the state to any angle in the XY-plane, and spread out the noise among different angles, which enabled us to extract the CNOT parameters from curve fitting. The CNOT finder yielded two sets of parameters for the gate, with a global phase of 90 degrees between them. The CNOT gate found by this method was validated by two-qubit randomized benchmarking (RB).

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Presenters

  • Yilun Xu

    Lawrence Berkeley National Laboratory

Authors

  • Yilun Xu

    Lawrence Berkeley National Laboratory

  • Gang Huang

    Lawrence Berkeley National Laboratory

  • Ravi K. Naik

    University of California, Berkeley, Univ of California – Berkeley, Physics, University of California, Berkeley, University of California Berkeley, Univ of California - Berkeley, Quantum Nanoelectronics Laboratory, Dept. of Physics, University of California, Berkeley, University of California - Berkeley

  • Alexis Morvan

    University of California, Berkeley, Lawrence Berkeley National Laboratory, Laboratoire de Physique des Solides, CNRS - Université Paris Saclay

  • Kasra Nowrouzi

    Lawrence Berkeley National Laboratory

  • Brad Mitchell

    University of California, Berkeley, Univ of California – Berkeley, University of California - Berkeley

  • David Ivan Santiago

    Lawrence Berkeley National Laboratory, University of California, Berkeley, Lawrence Berkely National Laboratory, Quantum Nanoelectronics Laboratory, Dept. of Physics, University of California, Berkeley

  • Irfan Siddiqi

    Lawrence Berkeley National Laboratory, University of California, Berkeley, Univ of California - Berkeley, Univ of California – Berkeley, Quantum Nanoelectronics Lab, UC Berkeley, Physics, University of California, Berkeley, Quantum Nanoelectronics Laboratory, Dept. of Physics, University of California, Berkeley