On the low-temperature phase of the three-state antiferromagnetic Potts model on the simple cubic lattice

TL;DR

This paper investigates the low-temperature phase of the three-state antiferromagnetic Potts model on a simple cubic lattice using advanced cluster variation methods, revealing the stability of a broken-sublattice-symmetry phase.

Contribution

It applies the cluster variation method in cube and star-cube approximations to analyze phase stability, providing new insights into the model's low-temperature behavior.

Findings

Broken-sublattice-symmetry phase is stable at low temperatures.

Star-cube approximation yields smaller free energy differences.

Contradicts previous results suggesting phase instability.

Abstract

The three-state antiferromagnetic Potts model on the simple cubic lattice is investigated using the cluster variation method in the cube and the star-cube approximations. The broken-sublattice-symmetry phase is found to be stable in the whole low-temperature region, contrary to previous results obtained using a modified cluster variation method. The tiny free energy difference between the broken-sublattice-symmetry and the permutationally-symmetric-sublattices phases is calculated in the two approximations and turns out to be smaller in the (more accurate) star-cube approximation than in the cube one.