Integrable Ladder t-J Model with Staggered Shift of the Spectral Parameter

TL;DR

This paper introduces an integrable t-J ladder model with a staggered spectral parameter shift, extending Yang-Baxter equations with Z_2 grading, and analyzes its eigenstates and thermodynamic properties.

Contribution

It generalizes Yang-Baxter equations with Z_2 grading and constructs a new integrable t-J ladder model with staggered spectral shifts and three-site interactions.

Findings

The model involves three-neighbor site interactions, resembling a zig-zag ladder.

Eigenstates and eigenvalues are obtained via Algebraic Bethe Ansatz.

In the thermodynamic limit, the ground state corresponds to quarter filling of fermions.

Abstract

The generalization of the Yang-Baxter equations (YBE) in the presence of Z_2 grading along both chain and time directions is presented and an integrable model of t-J type with staggered disposition along a chain of shifts of the spectral parameter is constructed. The Hamiltonian of the model is computed in fermionic formulation. It involves three neighbour site interactions and therefore can be considered as a zig-zag ladder model. The Algebraic Bethe Ansatz technique is applied and the eigenstates, along with eigenvalues of the transfer matrix of the model are found. In the thermodynamic limit, the lowest energy of the model is formed by the quarter filling of the states by fermions instead of usual half filling.