Extensible quantum circuit for the surface-code error correction cycle with frequency-tunable transmon qubits

ORAL

Abstract

We propose an extensible scheme for implementing the surface-code error correction cycle with fast-frequency-tuneable transmon qubits in a circuit QED architecture. This solution consists of a spatially repeating unit cell circuit with four data-carrying qubits, four ancillary qubits, four frequencies for single-qubit control, and eight frequency excursions for conditional-phase (C-Z) gates. By pipelining the interaction and ancilla measurement steps of $X$- and $Z$-type stabilizers, we engineer the frequency excursion patterns to avoid transmon-transmon interactions except the $|11\rangle-|02\rangle|$ avoided crossings exploited in C-Z gates. This scheme is amenable to planar and hole-based implementations of the surface code and to lattice surgery. Crucially, it allows the expansion of the surface-code fabric by spatial repetition and maximal exploitation of spatial and frequency multiplexing in the control architecture.

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Authors

  • Richard Versluis

    QuTech and TNO, Delft

  • Stefano Poletto

    QuTech and Kavli Institute of Nanoscience, Delft University of Technology, The Netherlands

  • Nader Khammassi

    QuTech, Computer Engineering Lab, Delft University of Technology, The Netherlands

  • Koen Bertels

    QuTech, Computer Engineering Lab and Kavli Institute of Nanoscience, Delft University of Technology, The Netherlands

  • Leonardo DiCarlo

    QuTech and Kavli Institute of Nanoscience, TU Delft, The Netherlands, QuTech and Kavli Institute of Nanoscience, Delft University of Technology, The Netherlands, QuTech and the Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands, QuTech and Kavli Institute of Nanoscience, Delft University of Technology and Intel Corporation, QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands, QuTech and Kavli Institute of Nanoscience, Delft University of Technology