Dynamic and spectral mixing in nanosystems

TL;DR

This paper investigates how dynamic and spectral mixing phenomena influence quantum behavior in nanosystems using a spin-boson model, revealing parameter-dependent stochastic-like effects observable via femtosecond spectroscopy.

Contribution

It introduces a semi-quantitative analysis of spectral and dynamic mixing effects in nanosystems within a spin-boson framework, supported by numerical validation.

Findings

Quantum evolution is governed by a key dimensionless parameter.

Both spectral and dynamic mixing induce stochastic-like behavior.

Results suggest observable effects in femtosecond spectroscopy experiments.

Abstract

In the framework of simple spin-boson Hamiltonian we study an interplay between dynamic and spectral roots to stochastic-like behavior. The Hamiltonian describes an initial vibrational state coupled to discrete dense spectrum reservoir. The reservoir states are formed by three sequences with rationally independent periodicities typical for vibrational states in many nanosize systems. We show that quantum evolution of the system is determined by a dimensionless parameter which is characteristic number of the reservoir states relevant for the initial vibrational level dynamics. Our semi-quantitative analytic results are confirmed by numerical solution of the equation of motion. We anticipate that predicted in the paper both kinds of stochastic-like behavior (namely, due to spectral mixing and recurrence cycle dynamic mixing) can be observed by femtosecond spectroscopy methods in nanosystems.