Dissipation and decoherence by ideal quantum gas

TL;DR

This paper derives the effective dynamics of a test particle in an ideal quantum gas, revealing diffusive forces and decoherence effects, including friction and anisotropic decoherence at zero temperature.

Contribution

It introduces a novel calculation of the effective Lagrangian using the closed time path formalism, highlighting new decoherence phenomena in ideal quantum gases.

Findings

Identifies diffusive effective forces acting on the particle.

Discovers anisotropic decoherence effects at zero temperature.

Derives a pure Newtonian friction force in the model.

Abstract

The effective Lagrangian of a test particle, interacting with an ideal gas, is calculated with in the closed time path formalism in the one-loop and the leading order of the particle trajectory. The expansion in the time derivative is available for slow enough motion and it uncovers diffusive effective forces and decoherence for the coordinate and the momentum. A pure Newtonian friction force and an anisotrop coordinate decoherence are found for zero temperature ideal gas of fermions.