A theory of dynamical control by modulation for optimal decoherence reduction is developed. It is based on the non-Markovian Euler-Lagrange equation for the energy-constrained field that minimizes the average dephasing rate of a qubit for any given dephasing spectrum.
@article{arxiv.0804.2691,
title = {Optimal Dynamical Decoherence Control of a Qubit},
author = {Goren Gordon and Gershon Kurizki and Daniel A. Lidar},
journal= {arXiv preprint arXiv:0804.2691},
year = {2008}
}