Quantum dynamics of nanosystems with nonequidistant spectrum

Abstract

A quantum problem of the evolution of a system coupled to a reservoir for which the interlevel spacing monotonically increases or decreases with increasing energy was solved. It was demonstrated that, despite the absence of an unambiguous definition of the recurrence cycle period, there is a wide range of parameters within which the basic feature of the evolution of system with an equidistant spectrum persist: the existence of the Loschmidt echo and mixing of the cycles that initiates the transition from a regular to a stochastic dynamic behavior. The results predict the existence of nonergodic nanosystems in which, as they evolve, energy periodically concentrates on certain vibrational degrees of freedom.