Finite size and temperature effects in the AF Heisenberg model

TL;DR

This paper investigates how finite size and temperature influence the properties of the 2+1 dimensional antiferromagnetic quantum Heisenberg model, focusing on magnon excitations and key physical constants.

Contribution

It provides a detailed analysis of low temperature and large volume effects, controlling corrections through spin stiffness, spin wave velocity, and staggered magnetization.

Findings

Corrections to free energy and ground state energy are quantified.

Low-lying excitations and susceptibilities are characterized.

Special limits of very low temperature and infinite volume are explored.

Abstract

The low temperature and large volume effects in the d=2+1 antiferromagnetic quantum Heisenberg model are dominated by magnon excitations. The leading and next-to-leading corrections are fully controlled by three physical constants, the spin stiffness, the spin wave velocity and the staggered magnetization. Among others, the free energy, the ground state energy, the low lying excitations, staggered magnetization, staggered and uniform susceptibilities are studied here. The special limits of very low temperature and infinite volume are considered also.