Spectral properties of a partially spin-polarized one-dimensional Hubbard/Luttinger superfluid

TL;DR

This paper investigates the excitation spectra of a spin-polarized Hubbard chain away from half-filling, revealing how spin-charge separation and superfluid properties are affected by polarization using advanced numerical methods.

Contribution

It provides detailed momentum-resolved spectra for a polarized Hubbard chain, highlighting modifications in spin-charge separation and superfluid behavior due to polarization.

Findings

Identification of a quasi-condensate at nonzero momentum proportional to polarization

Altered spin-charge separation in the polarized system

Detailed spectra for single-fermion, pair, density, and spin excitations

Abstract

We calculate the excitation spectra of a spin-polarized Hubbard chain away from half-filling, using a high-precision momentum-resolved time-dependent Density Matrix Renormalization Group method. Focusing on the U<0 case, we present in some detail the single-fermion, pair, density and spin spectra, and discuss how spin-charge separation is altered for this system. The pair spectra show a quasi-condensate at a nonzero momentum proportional to the polarization, as expected for this Fulde-Ferrel-Larkin-Ovchinnikov-like superfluid.