Bang-bang control of a qubit coupled to a quantum critical spin bath
Davide Rossini, Paolo Facchi, Rosario Fazio, Giuseppe Florio, Daniel A. Lidar, Saverio Pascazio, Francesco Plastina, Paolo Zanardi · Physical Review A · 2008
We analytically and numerically study the effects of pulsed control on the decoherence of a qubit coupled to a quantum spin bath. When the environment is critical, decoherence is faster and we show that the control is relatively more effective. Two coupling models are investigated, namely, a qubit coupled to a bath via a single link and a spin-star model, yielding results that are similar and consistent.