Universal quasi-Fermi liquid physics of one-dimensional interacting fermions

TL;DR

This paper introduces a universal class of one-dimensional spinless fermion models exhibiting quasi-Fermi liquid behavior, combining features of Luttinger and Fermi liquids due to irrelevant interactions, and characterized by unique spectral and momentum distribution properties.

Contribution

It identifies a universal quasi-Fermi liquid phase in 1D fermion systems, demonstrating its features through matrix product state calculations and showing its robustness across models and energy scales.

Findings

Finite discontinuity in momentum distribution at Fermi level

Power-law singularities in spectral function protected by symmetry

Emergence of Landau quasiparticles away from half-filling

Abstract

We present a class of one-dimensional generic spinless fermion lattice Hamiltonians that express quasi-Fermi liquid physics, manifesting both Luttinger and Fermi liquid features due to solely irrelevant interactions. Using infinite matrix product state techniques, we unveil its universal structure by calculating static and dynamic responses. Key features include a finite discontinuity in the momentum distribution at the Fermi level, despite power-law singularities in the spectral function protected by particle-hole symmetry. Away from half-filling Landau quasiparticles emerge. Charge dynamics show either high-energy bound states or concentration of spectral weight within the continuum for attractive or repulsive interactions, respectively. These universal features are realized across multiple models and energy scales thus reifying the quasi-Fermi liquid as a unique paradigm for one-dimensional fermions.