Binding of holons and spinons in the one-dimensional anisotropic t-J model

TL;DR

This paper investigates how holon-spinon binding in the one-dimensional anisotropic t-J model varies with anisotropy, revealing a transition from impurity-like to shallow bound states, supported by theoretical and numerical methods.

Contribution

It provides a detailed analysis of holon-spinon binding evolution with anisotropy using Bethe-Salpeter, exact diagonalization, and DMRG methods.

Findings

Holon-spinon binding varies significantly with anisotropy parameter lpha.

Binding is impurity-like in the Ising limit and becomes shallow near isotropic case.

Theoretical results agree well with numerical simulations, linking binding change to spinon spectrum evolution.

Abstract

We study the binding of a holon and a spinon in the one-dimensional anisotropic t-J model using a Bethe-Salpeter equation approach, exact diagonalization, and density matrix renormalization group methods on chains of up to 128 sites. We find that holon-spinon binding changes dramatically as a function of anisotropy parameter \alpha=J_\perp/J_z: it evolves from an exactly deducible impurity-like result in the Ising limit to an exponentially shallow bound state near the isotropic case. A remarkable agreement between the theory and numerical results suggests that such a change is controlled by the corresponding evolution of the spinon energy spectrum.