Exact Solution of the Biquadratic Spin-1 t-J Model in One Dimension

TL;DR

This paper introduces and exactly solves a generalized one-dimensional t-J model for spin-1 fermions using Bethe-ansatz, revealing both massless and massive excitations and indications of Cooper-like pairing.

Contribution

It presents a new exactly solvable spin-1 t-J model with biquadratic interactions, extending previous SU(N) models and uncovering novel excitation spectra and pairing phenomena.

Findings

Presence of both massless and massive excitations.

Evidence of Cooper-type pairs with finite binding energy.

Exact Bethe-ansatz solution for the model.

Abstract

A new generalization of the t-J model with a nearest-neigbor hopping is formulated and solved exactly by the Bethe-ansatz method. The model describes the dynamics of spin-S fermions with isotropic or anisotropic interactions. In the case S=1 the magnetic interaction is biquadratic in the spin operators. In contrast to the SU(N) generalization of the t-J model, studied previously in the literature, the present model possesses beyond a massless excitation also a massive one. The physical properties indicate the existence of Cooper-type pairs with finite binding energy.