Document Type

Article

Publication Date

5-17-2007

Publication Title

Physical Review B - Condensed Matter and Materials Physics

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 the 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 into saturation is obtained for a simple echo protocol, in good agreement with numerical results.

DOI

10.1103/PhysRevB.75.201302

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