On loss of quantum coherence in an interacting Fermi gas

TL;DR

This paper clarifies the path integral approach to an interacting Fermi gas, demonstrating that quasiparticles remain fully coherent at zero temperature when recoil effects are properly included.

Contribution

It corrects previous claims by showing that quasiparticles do not lose coherence at zero temperature when recoil is considered in the path integral calculation.

Findings

Quasiparticles remain coherent as T approaches 0.

Recoil effects are crucial in the path integral analysis.

Contradicts earlier claims of decoherence at zero temperature.

Abstract

We clarify the path integral calculation, recently suggested by Golubev and Zaikin, and show, contrary to their claim, that quasiparticles become fully coherent quantum particles in the $T \to 0$ limit. The important physical point is the inclusion of the recoil of the quasiparticle when interacting with fluctuations in the rest of the Fermi gas.