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Title: Three-stage decoherence dynamics of an electron spin qubit in an optically active quantum dot

Abstract

We report the control of solid-state qubits requires a detailed understanding of the decoherence mechanisms. Despite considerable progress in uncovering the qubit dynamics in strong magnetic fields, decoherence at very low magnetic fields remains puzzling, and the role of quadrupole coupling of nuclear spins is poorly understood. For spin qubits in semiconductor quantum dots, phenomenological models of decoherence include two basic types of spin relaxation: fast dephasing due to static but randomly distributed hyperfine fields (~2 ns) and a much slower process (>1 μs) of irreversible monotonic relaxation due either to nuclear spin co-flips or other complex many-body interaction effects. Here we show that this is an oversimplification; the spin qubit relaxation is determined by three rather than two distinct stages. Finally, the additional stage corresponds to the effect of coherent precession processes that occur in the nuclear spin bath itself, leading to a relatively fast but incomplete non-monotonic relaxation at intermediate timescales (~750 ns).

Authors:
 [1];  [1]; ORCiD logo [2];  [1];  [1];  [3];  [3]; ORCiD logo [2];  [1]
  1. Technische Universität München, Garching (Germany)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Technische Universität München, Garching (Germany); Stanford Univ., CA (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1492646
Report Number(s):
LA-UR-15-24203
Journal ID: ISSN 1745-2473
Grant/Contract Number:  
89233218CNA000001; AC52-06NA25396
Resource Type:
Accepted Manuscript
Journal Name:
Nature Physics
Additional Journal Information:
Journal Volume: 11; Journal Issue: 12; Journal ID: ISSN 1745-2473
Publisher:
Nature Publishing Group (NPG)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; decoherence; quantum dot; spin bath

Citation Formats

Bechtold, Alexander, Rauch, Dominik, Li, Fuxiang, Simmet, Tobias, Ardelt, Pier-Lennart, Regler, Armin, Muller, Kai, Sinitsyn, Nikolai A., and Finley, Jonathan J. Three-stage decoherence dynamics of an electron spin qubit in an optically active quantum dot. United States: N. p., 2015. Web. doi:10.1038/nphys3470.
Bechtold, Alexander, Rauch, Dominik, Li, Fuxiang, Simmet, Tobias, Ardelt, Pier-Lennart, Regler, Armin, Muller, Kai, Sinitsyn, Nikolai A., & Finley, Jonathan J. Three-stage decoherence dynamics of an electron spin qubit in an optically active quantum dot. United States. doi:10.1038/nphys3470.
Bechtold, Alexander, Rauch, Dominik, Li, Fuxiang, Simmet, Tobias, Ardelt, Pier-Lennart, Regler, Armin, Muller, Kai, Sinitsyn, Nikolai A., and Finley, Jonathan J. Mon . "Three-stage decoherence dynamics of an electron spin qubit in an optically active quantum dot". United States. doi:10.1038/nphys3470. https://www.osti.gov/servlets/purl/1492646.
@article{osti_1492646,
title = {Three-stage decoherence dynamics of an electron spin qubit in an optically active quantum dot},
author = {Bechtold, Alexander and Rauch, Dominik and Li, Fuxiang and Simmet, Tobias and Ardelt, Pier-Lennart and Regler, Armin and Muller, Kai and Sinitsyn, Nikolai A. and Finley, Jonathan J.},
abstractNote = {We report the control of solid-state qubits requires a detailed understanding of the decoherence mechanisms. Despite considerable progress in uncovering the qubit dynamics in strong magnetic fields, decoherence at very low magnetic fields remains puzzling, and the role of quadrupole coupling of nuclear spins is poorly understood. For spin qubits in semiconductor quantum dots, phenomenological models of decoherence include two basic types of spin relaxation: fast dephasing due to static but randomly distributed hyperfine fields (~2 ns) and a much slower process (>1 μs) of irreversible monotonic relaxation due either to nuclear spin co-flips or other complex many-body interaction effects. Here we show that this is an oversimplification; the spin qubit relaxation is determined by three rather than two distinct stages. Finally, the additional stage corresponds to the effect of coherent precession processes that occur in the nuclear spin bath itself, leading to a relatively fast but incomplete non-monotonic relaxation at intermediate timescales (~750 ns).},
doi = {10.1038/nphys3470},
journal = {Nature Physics},
number = 12,
volume = 11,
place = {United States},
year = {2015},
month = {9}
}

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