High-Fidelity Controlled-Z Gate with Maximal Intermediate Leakage Operating at the Speed Limit in a Superconducting Quantum Processor

V. Negîrneac, H. Ali, N. Muthusubramanian, F. Battistel, R. Sagastizabal, M. S. Moreira, J. F. Marques, W. J. Vlothuizen, M. Beekman, C. Zachariadis, N. Haider, A. Bruno, and L. DiCarlo
Phys. Rev. Lett. 126, 220502 – Published 4 June 2021
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Abstract

Simple tuneup of fast two-qubit gates is essential for the scaling of quantum processors. We introduce the sudden variant (SNZ) of the net zero scheme realizing controlled-Z (CZ) gates by flux control of transmon frequency. SNZ CZ gates realized in a multitransmon processor operate at the speed limit of transverse coupling between computational and noncomputational states by maximizing intermediate leakage. Beyond speed, the key advantage of SNZ is tuneup simplicity, owing to the regular structure of conditional phase and leakage as a function of two control parameters. SNZ is compatible with scalable schemes for quantum error correction and adaptable to generalized conditional-phase gates useful in intermediate-scale applications.

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  • Received 3 September 2020
  • Accepted 6 April 2021

DOI:https://doi.org/10.1103/PhysRevLett.126.220502

© 2021 American Physical Society

Physics Subject Headings (PhySH)

Quantum Information, Science & Technology

Authors & Affiliations

V. Negîrneac1,2,*, H. Ali1,3,*, N. Muthusubramanian1,3, F. Battistel1, R. Sagastizabal1,3, M. S. Moreira1,3, J. F. Marques1,3, W. J. Vlothuizen1,4, M. Beekman1,4, C. Zachariadis1,3, N. Haider1,4, A. Bruno1,3, and L. DiCarlo1,3

  • 1QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
  • 2Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal
  • 3Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
  • 4Netherlands Organisation for Applied Scientific Research (TNO), P.O. Box 96864, 2509 JG The Hague, Netherlands

  • *These authors contributed equally to this work.

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Issue

Vol. 126, Iss. 22 — 4 June 2021

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