Contractivity of time-dependent driven-dissipative systems

Abstract

Experimentally relevant quantum systems are frequently described by a time-dependent Lindblad master equation in which the dissipation due to interaction with an environment is fixed, but the experimenter has control over the Hamiltonian, which therefore can change with time. A fundamental question that is also of practical relevance is to determine when such systems invariably lose information about their initial state (are exponentially contractive independent of the Hamiltonian) or when the control can be used to prevent this loss of information to some degree. Here, we identify the necessary and sufficient criterion on the dissipator for Hamiltonian-invariant contractivity. If the dissipator does not fulfil this criterion, but by itself is exponentially contractive, we also establish exponential contractivity for sufficiently weak or slow drives and construct examples where strong or fast driving prevents exponential contraction.

35 pages, 1 figure