arXiv:1111.3722 · Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences
Non-Markovianity: initial correlations and nonlinear optical measurements
Arend G. Dijkstra, Yoshitaka Tanimura
Abstract
By extending the response function approach developed in nonlinear optics, we analytically derive an expression for the non-Markovianity in the time evolution of a system in contact with a quantum mechanical bath, and find a close connection with the directly observable nonlinear optical response. The result indicates that memory in the bath-induced fluctuations rather than in the dissipation causes non-Markovianity. Initial correlations between states of the system and the bath are shown to be essential for a correct understanding of the non-Markovianity. These correlations are included in our treatment through a preparation function.