Eur. Phys. J. B 48, 157-165 (2005)
https://doi.org/10.1140/epjb/e2005-00390-1

Numerical and Monte Carlo Bethe ansatz method: 1D Heisenberg model

¹ Department of Physics and Institute of Theoretical Physics, The Chinese University of Hong Kong, Hong Kong, P.R. China
² Departamento de Física e Centro de Física da Universidade do Minho, Campus Gualtar, 4700-320 Braga, Portugal
³ Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou 310027, P.R. China

Corresponding author: ^a sjgu@phy.cuhk.edu.hk

Received: 28 April 2005
Revised: 7 July 2005
Published online: 16 December 2005

Abstract

In this paper we present two new numerical methods for studying thermodynamic quantities of integrable models. As an example of the effectiveness of these two approaches, results from numerical solutions of all sets of Bethe ansatz equations, for small Heisenberg chains, and Monte Carlo simulations in quasi-momentum space, for a relatively larger chains, are presented. Our results agree with those obtained by the thermodynamic Bethe ansatz (TBA). As an application of these ideas, the pairwise entanglement between two nearest neighbors at finite temperatures is studied.