A high-temperature limit penalizing high-frequency quantum fluctuations

TL;DR

This paper introduces a new high-temperature limit in the Caldeira-Leggett model, revealing a mechanism for classicalizing high-frequency quantum fluctuations and deriving a Lindblad-form Markovian master equation.

Contribution

It derives an additional decoherence contribution at high temperatures and large cut-off frequencies, advancing understanding of quantum-to-classical transition mechanisms.

Findings

Reveals a novel decoherence mechanism for high-frequency fluctuations

Derives a Lindblad-form Markovian master equation

Analyzes the behavior of the decoherence kernel over time

Abstract

We revisit the Caldeira-Leggett model of quantum Brownian motion with Ohmic spectral density, and derive an additional contribution to the decoherence kernel in a new high-temperature limit at arbitrarily large cut-off frequency. This contribution reveals a novel mechanism for the classicalization of high-frequency quantum fluctuations. We further demonstrate that it leads to a Markovian master equation that is in guaranteed Lindblad form. Our approach considers in detail the behavior of the decoherence kernel at both the initial and final times of the process on the time scale of the bath memory.