Intertwined spin and charge dynamics in one-dimensional supersymmetric t-J model

TL;DR

This paper uses Bethe ansatz to analyze the dynamical spectra of the 1D supersymmetric t-J model, revealing fractionalized excitations and bound states that elucidate spin-charge separation and collective behaviors.

Contribution

It provides a detailed Bethe ansatz analysis of the dynamical spectra, identifying fractionalized excitations and bound states in the supersymmetric t-J model, advancing understanding of spin-charge separation.

Findings

Identification of fractionalized spin and charge excitations.

Observation of bound states via Bethe strings.

Connection of excitations to the half-filling limit.

Abstract

Following the Bethe ansatz we determine the dynamical spectra of the one-dimensional supersymmetric t-J model. A series of fractionalized excitations are identified through two sets of Bethe numbers. Typical patterns in each set are found to yield wavefunctions containing elementary spin and charge carriers, manifested as distinct boundaries of the collective excitations in the spectra of single electron Green functions. In spin channels, gapless excitations fractionalized into two spin and a pair of postive and negative charge carriers, extending to finite energy as multiple continua. These patterns connect to the half-filling limit where only fractionalized spinons survive. In particle density channel, apart from spin-charge fractionalization, excitations involving only charge fluctuations are observed. Furthermore, nontrivial Bethe strings encoding bound state structure appear in channels of reducing or conserving magnetization, where spin and charge constituents can also be identified. These string states contribute significantly even to the low-energy sector in the limit of vanishing magnetization.