Ferromagnetic Luttinger Liquids

TL;DR

This paper investigates ferromagnetic behavior in one-dimensional Fermi systems, revealing unique spin fluctuation propagation and spectral properties through perturbation theory and bosonization techniques.

Contribution

It introduces a detailed analysis of ferromagnetism in 1D Fermi systems, highlighting the ballistic spin fluctuations and their impact on spectral functions, which is a novel insight.

Findings

Longitudinal spin fluctuations propagate ballistically with velocity v_m << v_F.

Large anomalous dimension in the spin-channel affects spectral functions.

Strong algebraic singularities occur in the spectral function and structure factor for specific momentum transfers.

Abstract

We study weak itinerant ferromagnetism in one-dimensional Fermi systems using perturbation theory and bosonization. We find that longitudinal spin fluctuations propagate ballistically with velocity v_m << v_F, where v_F is the Fermi velocity. This leads to a large anomalous dimension in the spin-channel and strong algebraic singularities in the single-particle spectral function and in the transverse structure factor for momentum transfers q ~ 2 Delta/v_F, where 2 Delta is the exchange splitting.