Critical dynamics of decoherence

We study decoherence induced by a dynamic environment undergoing a quantum phase transition. The environment's susceptibility to perturbations-and, consequently, the efficiency of decoherence-is amplified near a critical point. Over and above this near-critical susceptibility increase, we show that decoherence is dramatically enhanced by the nonequilibrium critical dynamics of the environment. We derive a simple expression relating decoherence to the universal critical exponents exhibiting deep connections with the theory of topological defect creation in nonequilibrium phase transitions.