Decoherence due to thermal effects in two quintessential quantum systems

TL;DR

This paper investigates how thermal effects induce decoherence in two quantum systems, potentially suppressing observable quantum forces like Casimir and Aharonov-Bohm effects at finite temperatures.

Contribution

It provides a theoretical analysis of thermal decoherence in quantum forces, linking these effects to a quantum fluctuation-dissipation theorem and predicting temperature-dependent suppression.

Findings

Thermal effects can remove the angular dependence of Casimir forces.

Decoherence time is approximately h/(k_B T), affecting force observability.

Thermal decoherence may significantly suppress topological Aharonov-Bohm forces.

Abstract

Decoherence effects at finite temperature (T) are examined for two manifestly quantum systems: (i) Casimir forces between parallel plates that conduct along different directions, and (ii) a topological Aharonov-Bohm (AB) type force between fluxons in a superconductor. As we illustrate, standard path integral calculations suggest that thermal effects may remove the angular dependence of the Casimir force in case (i) with a decoherence time set by h/(k_{B} T) where h is Plank's constant and k_{B} is the Boltzmann constant. This prediction may be tested. The effect in case (ii) is due a phase shift picked by unpaired electrons upon encircling an odd number of fluxons. In principle, this effect may lead to small modifications in Abrikosov lattices. While the AB forces exist at extremely low temperatures, we find that thermal decoherence may strongly suppress the topological force at experimentally pertinent finite temperatures. It is suggested that both cases (i) and (ii) (as well as other examples briefly sketched) are related to a quantum version of the fluctuation-dissipation theorem.