Diffusion in the presence of correlated dynamical disorder and coherent exciton transfer in the non-Markovian limit

Abstract: The presence of static off-diagonal disorder promotes coherent exciton transport while diffusive motion can be recovered in the presence of fluctuations in the diagonal and off-diagonal elements of the Hamiltonian. Here we study the crossover induced by correlated dynamical disorder.We uncover a novel role of the excited bath states (ExBS) in dictating quantum coherence and quantum transport in dissipative quantum systems interacting with correlated bath.We solve both analytically and numerically the temperature dependent Quantum Stochastic Liouville equation (TD-QSLE) to study temperature dependence of quantum coherence in both linear chains and cyclic trimer (first three subunits of Fenna-Matthews-Olson(FMO) and also heptamer) complexes, using Haken-Strobl-Reineker Hamiltonian. In the non-Markovian limit where the lowering of temperature induces long-lasting quantum coherences, ExBSnot only determines the lifetime of coherences but also dictates the long time population distribution. We find a parallelism between classical and quantum systems through transitions among excited bath states that provides a deeper insight about role of temperature in equilibrium distribution.The effects of dynamic disorder and excited bath stat eon quantum entanglement (through the calculation of concurrence) in single exciton manifold are demonstrated.