Exact solution of a spin-ladder model

TL;DR

This paper introduces an integrable spin-ladder model with exact solutions, revealing three ground state phases and analyzing quantum critical behavior at a specific coupling point.

Contribution

It presents an exactly solvable spin-ladder model with detailed phase analysis and critical behavior, advancing understanding of quantum phase transitions in such systems.

Findings

Identifies three distinct ground state phases.

Determines the quantum critical point at J=J_+^c.

Describes the nature of phase transitions and critical behavior.

Abstract

An integrable spin-ladder model with nearest-neighbor exchanges and biquadratic interactions is proposed. With the Bethe ansatz solutions of the model hamiltonian, it is found that there are three possible phases in the ground state, i.e., a rung-dimerized phase with a spin gap, and two massless phases. The possible fixed points of the system and the quantum critical behavior at the critical point $J=J_+^c$ are discussed.