title: Unraveling a Brownian particle's memory with effective mode chains.
abstract: Memory effects in quantum dynamical processes involving structured environments are presently difficult, if not impossible, to investigate using standard approaches. Progress can be made by transforming the environmental variables to a suitable chain representation which effectively performs a Markovian embedding of the dynamics. Here, we show that this effective-mode chain representation provides a unique way of unraveling the memory kernel κ(t) as a function of time. Truncated or Markov-closed chains with n effective modes exactly reproduce κ(t) to the 4nth order in time, up to an irrelevant constant of order κ(0)/n. These favorable convergence properties pave the way for efficient quantum simulations of fast (non-Markovian) processes by reduced dynamical models.
authors: Dipartimento di Chimica-Fisica ed Elettrochimica, Università degli Studi di Milano, v. Golgi 19, I-20133 Milano, Italy. rocco.martinazzo@unimi.it
authors: R
authors: R
authors: Martinazzo
authors: K H
authors: KH
authors: Hughes
authors: I
authors: I
authors: Burghardt