Dynamical control of electron spin coherence in a quantum dot: A theoretical study
Physical Review B
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
... al 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.