Efficient adaptive Bayesian estimation of a slowly fluctuating Overhauser field gradient

SciPost Physics, vol. 17

Abstract

Slow fluctuations of Overhauser fields are an important source for decoherence in spin qubits hosted in III-V semiconductor quantum dots. Focusing on the effect of the field gradient on double-dot singlet-triplet qubits, we present two adaptive Bayesian schemes to estimate the magnitude of the gradient by a series of free induction decay experiments. We concentrate on reducing the computational overhead, with a real-time implementation of the schemes in mind. We show how it is possible to achieve a significant improvement of estimation accuracy compared to more traditional estimation methods. We include an analysis of the effects of dephasing and the drift of the gradient itself.

Authors 4

1. Jacob Benestad

   Norwegian University of Science and Technology

   Affiliation as printed

   Norwegian University of Science and Technology

   Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway

2. Jan A. Krzywda Aachen Lorentz Institute and Leiden Institute of Advanced Computer Science

   Leiden University

   Affiliation as printed

   Leiden University

   Lorentz Institute and Leiden Institute of Advanced Computer Science, Leiden University, P.O. Box 9506, 2300 RA Leiden, The Netherlands

3. Evert van Nieuwenburg Aachen Lorentz Institute and Leiden Institute of Advanced Computer Science

   Leiden University

   Affiliation as printed

   Leiden University

   Lorentz Institute and Leiden Institute of Advanced Computer Science, Leiden University, P.O. Box 9506, 2300 RA Leiden, The Netherlands

4. Jeroen Danon corresponding

   Norwegian University of Science and Technology

   Affiliation as printed

   Norwegian University of Science and Technology

   Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway