Composite pulse sequences for Z-rotations robust against small magnetic field gradient in singlet-triplet qubits

ORAL

Abstract

We design piecewise composite pulse sequences of the exchange interaction in singlet-triplet qubits, suitable for achieving a Z-rotation along the Bloch sphere of arbitrary angle under the influence of a small stray magnetic field gradient. We explicitly show that upon appropriately choosing the pulse parameters, the error arising from the magnetic field gradient can be canceled at least to the third order. Examining the error as a function of the magnetic field gradient, we estimate the magnitude of fluctuation in the magnetic field gradient that can be tolerated under certain quantum error correction threshold.

*This work is supported by IARPA, LPS-CMTC and CNAM.

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Authors

  • Xin Wang

    • Condensed Matter Theory Center, University of Maryland, College Park
    • Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park

  • Edwin Barnes

    • Condensed Matter Theory Center, Dept. of Physics, University of Maryland
    • Condensed Matter Theory Center, University of Maryland, College Park
    • Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park

  • Lev Bishop

    • Joint Quantum Institute and Condensed Matter Theory Center, University of Maryland, College Park
    • Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park
    • Joint Quantum Institute and CMTC

  • Jason Kestner

    • Condensed Matter Theory Center, University of Maryland, College Park
    • Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park
    • Condensed Matter Theory Center, Department of Physics, University of Maryland - College Park

  • Kai Sun

    • University of Maryland
    • Condensed Matter Theory Center, University of Maryland, College Park
    • Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park
    • Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, MD 20742
    • University of Maryland, College Park

  • Sankar Das Sarma

    • Department of Physics, University of Maryland
    • Condensed Matter Theory Center, Dept. of Physics, University of Maryland
    • Condensed Matter Theory Center, University of Maryland, College Park
    • Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park
    • University of Maryland, College Park
    • Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, MD 20742
    • Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
    • CMTC, UMD, College Park