Phase Transition of Laminated Models at Any Temperature

TL;DR

This paper generalizes Pirogov-Sinai theory to models with dual interactions, demonstrating the existence of multiple phase transitions at any temperature, especially in (1+1)-dimensional systems, based on transversal interaction strength.

Contribution

It extends the theoretical framework to include models with both longitudinal and transversal interactions, proving phase transitions occur at all temperatures under broad conditions.

Findings

Models exhibit multiple phase transitions at any temperature.

Phase transition phenomena are demonstrated in (1+1)-dimensional systems.

Transversal interaction strength governs the phase behavior.

Abstract

The standard Pirogov -- Sinai theory is generalized to the class of models with two modes of interaction: longitudinal and transversal. Under rather general assumptions about the longitudinal interaction and for one specific form of the transversal interaction it is proved that such system has a variety of phase transitions at any temperature: the parameter which plays the role of inverse temperature is the strength of the transversal interaction. The concrete examples of such systems are $(1+1)$-dimensional models.