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Dynamical control of electron spin coherence in a quantum dot

Wenxian Zhang·V. V. Dobrovitski·Lea F. Santos·Lorenza Viola·B. N. Harmon
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Abstract

We investigate the performance of dynamical decoupling methods at suppressing electron spin decoherence from a low-temperature nuclear spin reservoir in a quantum dot. The controlled dynamics is studied through exact numerical simulation, with emphasis on realistic pulse delays and long-time limit. Our results show that optimal performance for this system is attained by a periodic protocol exploiting concatenated design, with control rates substantially slower than expected from the upper spectral cutoff of the bath. For a known initial electron spin state, coherence can saturate at long times, signaling the creation of a stable ``spin-locked'' decoherence-free subspace. Analytical insight on saturation is obtained for a simple echo protocol, in good agreement with numerical results.

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Wenxian Zhang, V. V. Dobrovitski, Lea F. Santos, Lorenza Viola, B. N. Harmon. 2007-01-21. Dynamical control of electron spin coherence in a quantum dot. https://doi.org/10.1103/physrevb.75.201302

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