Fast dynamics of molecular bridges

We address the dynamics of open quantum systems, when complex finite time initial conditions, an ensuing rapid nonequilibrium transient, quantum interferences and their attenuation play important roles. To study all these phenomena in conditions of general non-equilibrium, open systems are represented by a simple structure of a molecular island between two leads. We treat this model using the Nonequilibrium Greens Functions (NGF) method for a finite initial condition. We demonstrate that the non-interacting molecular bridge model captures well many features of general open quantum systems. Three stages of its nonequilibrium evolution, the first described by the full NGF description, the second, ruled by the asymptotically exact Generalized master equation (GME) and the third, governed by a Markovian master equation (ME), are delineated and related to each other.