title: Generalized quantum kinetic expansion: Time scale separation between intra-cluster and inter-cluster kinetics.
abstract: For a general two-cluster network, a new methodology of the cluster-based generalized quantum kinetic expansion (GQKE) is developed in the matrix formalism under two initial conditions: the local cluster equilibrium and system-bath factorized states. For each initial condition, the site population evolution follows exactly a distinct closed equation, where all the four terms involved are systematically expanded over inter-cluster couplings. For the system-bath factorized initial state, the numerical investigation of the two models, a biased (2, 1)-site system and an unbiased (2, 2)-site system, verifies the reliability of the GQKE and the relevance of higher-order corrections. The time-integrated site-to-site rates and the time evolution of site population reveal the time scale separation between intra-cluster and inter-cluster kinetics. The population evolution of aggregated clusters can be quantitatively described by the approximate cluster Markovian kinetics.
authors.affiliation: Physics Department, Zhejiang University, 38 ZheDa Road, Hangzhou, Zhejiang 310027, China.
authors.forename: Zhoufei
authors.initials: Z
authors.lastname: Tang
authors.affiliation: Physics Department, Zhejiang University, 38 ZheDa Road, Hangzhou, Zhejiang 310027, China.
authors.forename: Zhihao
authors.initials: Z
authors.lastname: Gong
authors.affiliation: Physics Department, Zhejiang University, 38 ZheDa Road, Hangzhou, Zhejiang 310027, China.
authors.forename: Jianlan
authors.initials: J
authors.lastname: Wu