High-Temperature Quantum Coherence from Dissipative Environments

TL;DR

This paper demonstrates that quantum oscillators can maintain high-temperature coherence due to dissipative environments, challenging the traditional view that coherence only exists at low temperatures.

Contribution

It introduces a theoretical framework showing how intermediate-temperature reservoirs can induce a coherent ground state in quantum oscillators, explaining high-temperature quantum phenomena.

Findings

At intermediate temperatures, the oscillator reaches a coherent ground state.

High-temperature environments can suppress excited modes, maintaining quantum coherence.

Thermalization occurs again at higher temperatures, restoring Boltzmann distribution.

Abstract

The Feynman-Vernon path integral formalism is used to derive the density matrix of a quantum oscillator that is linearly coupled to an environmental reservoir. Although low-temperature reservoirs thermalize the oscillator to the usual Boltzmann distribution, reservoirs at intermediate temperatures reduce this distribution to a single, coherent ground state. Associated with this state is an imaginary frequency indicating an environment which absorbs energy from the oscillator through the suppression of all excited modes. Further increase of the environmental temperature results again in the thermalization of the quantum oscillator to the expected Boltzmann distribution. Qualitatively, this result could account for high-temperature quantum effects including the superconducting properties of graphite grains as well as the quantum coherence observed in photosynthetic systems.