Dissipative dynamics in a quantum bistable system: Crossover from weak to strong damping

TL;DR

This paper studies the dissipative behavior of a quantum bistable system interacting with an Ohmic heat bath, revealing different dynamical regimes across various temperatures and coupling strengths.

Contribution

It introduces a new approximation scheme beyond the spin-boson model, enabling analysis of a broad parameter space in quantum dissipation dynamics.

Findings

Identification of different dynamical regimes in the phase diagram

Development of a generalized master equation for population dynamics

Analysis of crossover from weak to strong damping regimes

Abstract

The dissipative dynamics of a quantum bistable system coupled to a Ohmic heat bath is investigated beyond the spin-boson approximation. Within the path-integral approach to quantum dissipation, we propose an approximation scheme which exploits the separation of time scales between intra- and interwell (tunneling) dynamics. The resulting generalized master equation for the populations in a space localized basis enables us to investigate a wide range of temperatures and system-environment coupling strengths. A phase diagram in the coupling-temperature space is provided to give a comprehensive account of the different dynamical regimes.