Nonadditivity in Quasiequilibrium States of Spin Systems with Lattice Distortion

Abstract

It is pointed out that there exists a short-range interacting system, i.e. the elastic spin model, which is extensive but nonadditive. It is numerically shown that, depending on the statistical ensemble, the specific heat or the susceptibility becomes negative in a certain parameter region, which shows ensemble inequivalence in this model. Further, we numerically estimate the effective Hamiltonian for spin variables, and it is clarified that the effective interaction among spin variables is long-ranged. Remarkably, the so called Kac's prescription, which is usually regarded as a mathematical operation to make the system extensive, naturally holds in the effective interaction.

5 pages, substantially revised; some minor revisions, to appear in Phys. Rev. Lett

References in corpus (3)

• Statistical mechanics and dynamics of solvable models with long-range interactions
• Simple Two-Dimensional Model for the Elastic Origin of Cooperativity among Spin States of Spin-Crossover Complexes
• Realization of the mean-field universality class in spin-crossover materials

Cited by in corpus (5)

• Phase transitions in systems with non-additive long-range interactions
• The Origin of Mean-Field Behavior in an Elastic Ising Model
• Perspective on Physical Interpretations of Rényi Entropy in Statistical Mechanics
• Existence of shape-dependent thermodynamic limit in spin systems with short- and long-range interactions
• Quasi-equilibrium nonadditivity