Topological crossovers near a quantum critical point

TL;DR

This paper investigates the topological changes in the Fermi surface of strongly correlated Fermi systems near a quantum critical point, revealing non-Fermi-liquid behavior and proposing experiments with liquid helium-3.

Contribution

It introduces the concept of topological crossovers affecting Fermi surface topology and their role in non-Fermi-liquid regimes in strongly correlated systems.

Findings

Identification of multi-connected Fermi surfaces beyond stability limits

Characterization of non-Fermi-liquid temperature regimes

Proposal of experiments with liquid $^3$He to test theoretical predictions

Abstract

We study the temperature evolution of the single-particle spectrum $\epsilon(p)$ and quasiparticle momentum distribution $n(p)$ of homogeneous strongly correlated Fermi systems beyond a point where the necessary condition for stability of the Landau state is violated, and the Fermi surface becomes multi-connected by virtue of a topological crossover. Attention is focused on the different non-Fermi-liquid temperature regimes experienced by a phase exhibiting a single additional hole pocket compared with the conventional Landau state. A critical experiment is proposed to elucidate the origin of NFL behavior in dense films of liquid $^3$He.