Hierarchical equations of motion method applied to nonequilibrium heat transport in model molecular junctions: Transient heat current and high-order moments of the current operator

摘要

We present a theoretical approach to study nonequilibrium quantum heat transport in molecular junctions describedby a spin-boson type model. Based on the Feynman-Vernon path integral influence functional formalism,expressions for the average value and high-order moments of the heat current operators are derived, which arefurther obtained directly from the auxiliary density operators (ADOs) in the hierarchical equations of motion(HEOM) method. Distribution of the heat current is then derived from the high-order moments. As the HEOMmethod is nonperturbative and capable of treating non-Markovian system-environment interactions, the methodcan be applied to various problems of nonequilibrium quantum heat transport beyond the weak coupling regime.