Physical Review B - Condensed Matter and Materials Physics
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.
Zhang, Wenxian; Dobrovitski, V. V.; Santos, Lea F.; Viola, Lorenza; and Harmon, B. N., "Dynamical Control of Electron Spin Coherence In a Quantum Dot: A Theoretical Study" (2007). Open Dartmouth: Faculty Open Access Articles. 1940.