Simulations of Magnetic Noise in Classical XY and Heisenberg Spin Models

ORAL

Abstract

Superconducting qubits show great promise but continue to be plagued by flux noise. Experiments show that surface spins are the source of this flux noise, and the noise has a power spectral density of the form 1/fα with the noise exponent α~1. Experiments also provide evidence for ferromagnetic exchange. We investigate to what extent ferromagnetic exchange is consistent the observed flux noise exponents. With input from density functional theory calculations of magnetic impurities, we present the results of Monte Carlo simulations of the magnetic noise produced by coupled classical XY and Heisenberg spins in 2D lattices. We find the parameters of the models that result in a noise exponent near 1.

*Google Gift No. 2502, University of California MRPI grant MRP-17-454755, DOE-BES Grant No. DE-FG02-05ER46237, NSF of China Grant No. 11474056, and National Basic Research Program of China grant 2015CB921400.

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Presenters

  • Daniel Mickelsen

    • Department of Physics and Astronomy, University of California, Irvine, CA, United States

Authors

  • Daniel Mickelsen

    • Department of Physics and Astronomy, University of California, Irvine, CA, United States

  • Hui Wang

    • Department of Physics and Astronomy, University of California, Irvine, CA, United States
    • Department of Physics and Astronomy, University of California, Irvine

  • Zhe Wang

    • Department of Physics, Fudan University, Shanghai, China
    • Fudan University

  • Ruqian Wu

    • University of California, Irvine
    • Department of Physics and Astronomy, University of California, Irvine, CA, United States
    • Fudan University
    • Department of Physics and Astronomy, University of California, Irvine

  • Clare C Yu

    • Department of Physics and Astronomy, University of California, Irvine, CA, United States