Collapse and revival of quantum coherence for a harmonic oscillator interacting with a classical fluctuating environment

TL;DR

This paper investigates how classical environmental fluctuations affect quantum coherence in a harmonic oscillator, revealing phenomena like coherence decay, revival, and the role of memory effects without using approximate quantum master equations.

Contribution

It introduces a stochastic modeling approach to analyze nonclassicality dynamics, capturing non-Markovian effects and coherence revival phenomena in a harmonic oscillator coupled to a classical fluctuating environment.

Findings

Classical memory effects prolong quantum coherence.

Detuning induces revival of quantum coherence.

Decoherence dynamics are described without approximate master equations.

Abstract

We address the dynamics of nonclassicality for a quantum system interacting with a noisy fluctuating environment described by a classical stochastic field. As a paradigmatic example, we consider a harmonic oscillator initially prepared in a maximally nonclassical state, e.g. a Fock number state or a Schroedinger cat-like state, and then coupled to either resonant or non-resonant external field. Stochastic modeling allows us to describe the decoherence dynamics without resorting to approximated quantum master equations, and to introduce non- Markovian effects in a controlled way. A detailed comparison among different nonclassicality criteria and a thorough analysis of the decoherence time reveal a rich phenomenology whose main features may be summarized as follows: i) classical memory effects increase the survival time of quantum coherence; ii) a detuning between the natural frequency of the system and the central frequency of the classical field induces revivals of quantum coherence.