Critical Properties of Spectral Functions for the 1D Anisotropic t-J Models with an Energy Gap

TL;DR

This paper calculates exact critical exponents for spectral functions in 1D anisotropic t-J models with energy gaps, revealing power-law singularities influenced by massive excitations, using Bethe ansatz and conformal field theory.

Contribution

It provides the first exact determination of momentum-dependent critical exponents in gapped 1D t-J models, linking spectral singularities to massive excitations.

Findings

Spectral functions exhibit power-law singularities at specific frequencies.

Massive spin or charge excitations control the singular behavior.

The approach combines Bethe ansatz with conformal field theory techniques.

Abstract

We exactly calculate the momentum-dependent critical exponents for spectral functions in the one-dimensional anisotropic t-J models with a gap either in the spin or charge excitation spectrum. Our approach is based on the Bethe ansatz technique combined with finite-size scaling techniques in conformal field theory. It is found that the spectral functions show a power-law singularity, which occurs at frequencies determined by the dispersion of a massive spin (or charge) excitation.We discuss how the nontrivial contribution of a massive excitation controls the singular behavior in optical response functions.