Anomalously long lifetimes in two-dimensional Fermi liquids

TL;DR

This paper develops a comprehensive method to analyze decay rates of Fermi surface perturbations in 2D electron liquids, revealing an exotic odd-parity transport regime with anomalously long-lived modes at accessible temperatures.

Contribution

It introduces a general basis expansion of the collision integral applicable at all temperatures, enabling detailed characterization of the odd-parity transport regime in 2D Fermi liquids.

Findings

Identification of an odd-parity regime with long-lived modes

Decay rates for Fermi surface perturbations across temperatures

Regime accessible at temperatures up to 0.1 T_F

Abstract

A precise characterization of the recently discovered crossover to hydrodynamic transport in electron liquids, and in particular of a conjectured exotic odd-parity transport regime, requires a full solution of the Fermi-liquid collision integral at all temperatures beyond state-of-the-art analytic leading-logarithmic approximations. We develop a general basis expansion of the linearized collision integral applicable at all temperatures, and employ this to determine the decay rates of Fermi surface perturbations in two-dimensional electron liquids. In particular, we provide exhaustive data on the decay rates for a new odd-parity regime, in which parity-even Fermi surface deformations decay rapidly but odd-parity modes are anomalously long lived. We find that this transport regime exists at fairly large temperatures $T \lesssim 0.1 T_F$, putting this regime within the reach of current experiments.