Spin excitations in the integrable open quantum group invariant supersymmetric t-J model

TL;DR

This paper analytically investigates spin excitations in an integrable supersymmetric t-J model with open boundaries, revealing an $su(2)$ symmetry near half-filling and calculating finite-size effects on surface spin excitations.

Contribution

It provides an analytic solution for the Bethe equations and finite-size corrections in the supersymmetric t-J model with open boundaries, highlighting $su(2)$ symmetry features.

Findings

$su(2)$ symmetry observed near half-filling

Finite-size corrections to eigenvalues calculated analytically

Surface effects on spin excitations characterized

Abstract

The integrable quantum group $spl_q(2,1)$-invariant supersymmetric t-J model with open boundaries is studied via an analytic treatment of the Bethe equations. An $su(2)$ feature is seen to hold for states at or close to half-filling. For these states the eigenvalues of the transfer matrix of the t-J model satisfy a set of $su(2)$ functional relations. The finite-size corrections to the relevant eigenvalues, and thus the surface effect on the spin excitations, have been calculated analytically by solving the functional relations.