Ordered Phase in the Fermionized Heisenberg Antiferromagnet

TL;DR

This paper investigates the thermal properties and phase order of the spin 1/2 Heisenberg Antiferromagnet using a fermionic representation, emphasizing the importance of the single occupancy constraint and fluctuation effects.

Contribution

It introduces a detailed analysis of the ordered phase considering the single occupancy constraint with a path integral approach and one-loop fluctuations.

Findings

Single occupancy constraint significantly affects thermal properties.

Fluctuations around the saddle point modify the phase behavior.

Method provides insights into fermionic representations of antiferromagnets.

Abstract

Thermal properties of the ordered phase of the spin 1/2 isotropic Heisenberg Antiferromagnet on a d-dimensional hypercubical lattice are studied within the fermionic representation when the constraint of single occupancy condition is taken into account by the method suggested by Popov and Fedotov. Using saddle point approximation in path integral approach we discuss not only the leading order but also the fluctuations around the saddle point at one-loop level. The influence of taking into account the single occupancy condition is discussed at all steps.