Dynamical decoupling

“Bang-Bang Control of a Qubit Coupled to a Quantum Critical Spin Bath”, Phys. Rev. A 77, 052112 (2008), by D. Rossini, P. Facchi, R. Fazio, G. Florio, D.A. Lidar, S. Pascazio, F. Plastina, and P. Zanardi [link]