Effect of bath temperature on the decoherence of quantum dissipative systems

TL;DR

This paper investigates how bath temperature affects decoherence in quantum dissipative systems, revealing that higher temperatures can either reduce or enhance decoherence depending on the coupling strength, indicating a dynamical transition.

Contribution

It introduces a novel analysis of temperature effects on decoherence using a hierarchical equations-of-motion approach without common approximations, uncovering a temperature-dependent transition in decoherence behavior.

Findings

Decoherence can be reduced by increasing bath temperature in strong-coupling regimes.

In weak-coupling regimes, higher bath temperature may enhance decoherence.

A critical transition point is characterized by changes in the quantum coherence spectrum.

Abstract

We report an anomalous decoherence phenomenon of a quantum dissipative system in the framework of a stochastic decoupling scheme along with a hierarchical equations-of-motion formalism without the usual Born-Markov or weak coupling approximations. It is found that the decoherence of a two-qubit spin-boson model can be reduced by increasing the bath temperature in strong-coupling regimes. For the weak-coupling situation, we find that the bath temperature may enhance the decoherence. This result is contrary to the common recognition that a higher bath temperature always induces a more severe decoherence and suggests that a decoherence dynamical transition occurs in this two-qubit spin-boson model. We also demonstrate that the critical transition point can be characterized by the behavior of the frequency spectrum of the quantum coherence indicator.