Spin-Glass Model for Inverse Freezing

TL;DR

This paper investigates the inverse freezing phenomenon in a disordered spin-1 model using the Blume-Emery-Griffiths framework, employing advanced replica symmetry breaking techniques to analyze phase transitions and compare with related models.

Contribution

It introduces a detailed analysis of inverse freezing in a disordered spin-1 model using the Full Replica Symmetry Breaking Ansatz, highlighting the Ghatak-Sherrington model's key features.

Findings

The model exhibits inverse freezing with a stable thermodynamic phase.

Comparison shows the Ghatak-Sherrington model captures essential inverse transition features.

Results align with generalized spin variable models and differ from lattice gas models.

Abstract

We analyze the Blume-Emery-Griffiths model with disordered magnetic interaction displaying the inverse freezing phenomenon. The behaviour of this spin-1 model in crystal field is studied throughout the phase diagram and the transition and spinodal lines for the model are computed using the Full Replica Symmetry Breaking Ansatz that always yelds a thermodynamically stable phase. We compare the results both with the quenched disordered model with Ising spins on lattice gas - where no reentrance takes place - and with the model with generalized spin variables recently introduced by Schupper and Shnerb [Phys. Rev. Lett. 93, 037202 (2004)]. The simplest version of all these models, known as Ghatak-Sherrington model, turns out to hold all the general features characterizing an inverse transition to an amorphous phase, including the right thermodynamic behavior.