Probing the coherence of solid-state qubits at avoided crossings

ORAL

Abstract

The avoided crossing of energy levels in spin defects can be both beneficial and detrimental to quantum information applications. The emergence of a clock transition enhances the protection from magnetic noise thus improving coherence times, while ground state level anti-crossings (GSLAC) can increase longitudinal relaxation rates. We investigate the dynamics of divacancy spin qubits in SiC at a clock transition and near the GSLAC using a combination of theory and experiments. We present a theoretical approach based on a generalization of the cluster expansion method. We characterize the decoherence mechanism of spin qubits at avoided crossings, the transition from quantum to classical noise, and the emergence of multiple clock transitions arising from strongly coupled nuclear spins. Combined with ab-initio predictions of spin Hamiltonian parameters, the proposed theoretical approach paves the way to designing the coherence properties of spin qubits from first principles. [1,2]

1. M. Onizhuk, K. C. Miao, J. P. Blanton, H. Ma, et al., ArXiv preprint:https://arxiv.org/abs/2010.11077
2. A. Bourassa, C.P. Anderson, K.C. Miao, M. Onizhuk, et al., Nat. Mater. 1-7 (2020)

*This work was supported by AFOSR FA9550-19-1-0358, NSF DMR-1420709, DARPA D18AC00015KK1932, and ONR N00014-17-1-3026.

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Presenters

  • Mykyta Onizhuk

    • University of Chicago
    • Pritzker School of Molecular Engineering, University of Chicago

Authors

  • Mykyta Onizhuk

    • University of Chicago
    • Pritzker School of Molecular Engineering, University of Chicago

  • Kevin Miao

    • Pritzker School of Molecular Engineering, University of Chicago
    • University of Chicago

  • Joseph Blanton

    • Pritzker School of Molecular Engineering, University of Chicago
    • University of Chicago

  • He Ma

    • Department of Chemistry, University of Chicago
    • Pritzker School of Molecular Engineering, University of Chicago
    • University of Chicago

  • Christopher Anderson

    • Pritzker School of Molecular Engineering, University of Chicago
    • Pritzker School for Molecular Engineering, University of Chicago
    • University of Chicago

  • Alexandre Bourassa

    • Pritzker School of Molecular Engineering, University of Chicago
    • University of Chicago

  • David Awschalom

    • University of Chicago
    • Pritzker School of Molecular Engineering, University of Chicago
    • Pritzker School for Molecular Engineering, University of Chicago
    • Center for Molecular Engineering, Materials Science Division, Argonne National Laboratory

  • Giulia Galli

    • The University of Chicago
    • Pritzker School of Molecular Engineering, The University of Chicago
    • Pritzker School of Molecular Engineering, University of Chicago
    • University of Chicago
    • Department of Chemistry, University of Chicago
    • Materials Science Division and Center for Molecular Engineering, Argonne National Laboratory