The XXZ model with anti-periodic twisted boundary conditions

TL;DR

This paper derives functional equations for the XXZ model with anti-diagonal twisted boundary conditions, confirming results with Baxter's method and analyzing finite size scaling of the ground state energy.

Contribution

It introduces a novel derivation of eigenvalue equations for the XXZ model with specific boundary conditions using fusion and separation of variables.

Findings

Functional equations match Baxter's results

Finite size scaling of ground state energy analyzed

Comparison with Galleas's recent solution

Abstract

We derive functional equations for the eigenvalues of the XXZ model subject to anti-diagonal twisted boundary conditions by means of fusion of transfer matrices and by Sklyanin's method of separation of variables. Our findings coincide with those obtained using Baxter's method and are compared to the recent solution of Galleas. As an application we study the finite size scaling of the ground state energy of the model in the critical regime.