2015/01/16 by Vera B. Henriques, Henriques, Vera B., S. R. Salinas +1
Economics, Econometrics and Finance · Physics and Astronomy · #Complex Systems and Time Series Analysis #FOS: Physical sciences #Quantum many-body systems #Statistical Mechanics (cond-mat.stat-mech) #Theoretical and Computational Physics
paper · pdf · doi:10.48550/arxiv.1501.04029
openalex publication_date 2015/01/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The equivalence of thermodynamic results in the canonical and the microcanonical ensembles has been questioned in some calculations for spin models with long-range interactions. We show that these claims of inequivalence are related to an inadequate definition of the independent (density) variables in the microcanonical ensemble. We illustrate this point with the example of a simple spin-1 ideal paramagnet, and then revisit the original calculations of Barré, Mukamel, and Ruffo, for a mean-field spin-1 Blume-Capel model. If the microcanonical ensemble is defined in terms of adequate density variables, we show that there is no disagreement with the calculations in the usual canonical ensemble (with fixed thermodynamic field variables).