Stochastic unraveling of positive quantum dynamics

Abstract

Stochastic unravelings represent a useful tool to describe the dynamics of open quantum systems and standard methods, such as quantum state diffusion (QSD), call for the complete positivity of the open-system dynamics. Here, we present a generalization of QSD, which also applies to positive, but not completely positive evolutions. The rate and the action of the diffusive processes involved in the unraveling are obtained by applying a proper transformation to the operators which define the master equation. The unraveling is first defined for semigroup dynamics and then extended to a definite class of time-dependent generators. We test our approach on a prototypical model for the description of exciton transfer, keeping track of relevant phenomena, which are instead disregarded within the standard, completely positive framework.

9 pages, 2 figures

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• Fermionic duality: General symmetry of open systems with strong dissipation and memory
• Dynamics of Open Quantum Systems with Initial System-Environment Correlations via Stochastic Unravelings
• Theoretical Limits of Protocols for Distinguishing Different Unravelings
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