Non-Markovian decay and dynamics of decoherence in private and public environments

TL;DR

This paper investigates how non-Markovian effects and the environment's spectral structure influence decoherence decay rates in quantum systems, comparing different environmental coupling scenarios and analytical models.

Contribution

It provides a detailed analysis of decay processes in open quantum systems with non-Markovian effects, highlighting differences between private and public environments and improving decay rate predictions.

Findings

Public environments cause greater deviations from FGR predictions.

Non-Markovian effects significantly alter decay rates.

Analytical and numerical methods show environment correlations impact decoherence.

Abstract

We study the decay process in an open system, emphasizing on the relevance of the environment's spectral structure. Non-Markovian effects are included to quantitatively analyze the degradation rate of the coherent evolution. The way in which a two level system is coupled to different environments is specifically addressed: multiple connections to a single bath (public environment)or single connections to multiple baths (private environments). We numerically evaluate the decay rate of a local excitation by using the Survival Probability and the Loschmidt Echo. These rates are compared to analytical results obtained from the standard Fermi Golden Rule (FGR) in Wide Band Approximation, and a Self-Consistent evaluation that accounts for the bath's memory in cases where an exact analytical solution is possible. We observe that the correlations appearing in a public bath introduce further deviations from the FGR as compared with a private bath.