Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2606.17691

First-order phase transitions in the three-dimensional Blume-Capel ferromagnet

D. Mataragkas·A. Vasilopoulos·Z. D. Vatansever·Y. Kim·D. -H. Kim·N. G Fytas
View original source ↗Read source document ↗Export metadata ↓

Abstract

We investigate first-order phase transitions in the three-dimensional Blume-Capel ferromagnet on the simple cubic lattice by combining multicanonical simulations with two-parameter Wang-Landau sampling. The generalized-ensemble approach enables a detailed characterization of the coexistence region over a broad range of temperatures and crystal-field couplings, extending from the vicinity of the tricritical point deep into the first-order regime. We analyze the finite-size scaling behavior of thermodynamic observables, with particular emphasis on the energy probability density function, free-energy barriers, and interfacial properties. The evolution of the double-peaked energy distributions reveals a gradual crossover from weak to strong first-order behavior as the temperature is lowered. From the scaling of the free-energy barrier we determine the interface tension along the coexistence line and characterize its approach to the tricritical region through its vanishing behavior. In parallel, a field-mixing analysis based on the joint density of states obtained from two-parameter Wang-Landau simulations is employed to locate first-order transition points and probe tricritical behavior. While this approach has been highly successful in two-dimensional realizations of the Blume-Capel model, we find that in three dimensions its practical implementation becomes increasingly sensitive in the vicinity of the tricritical region, where the shallow structure of the relevant scaling variable distribution limits the ability to resolve coexistence conditions for the system sizes currently accessible. These results delineate the range of applicability of the method in three dimensions and provide a consistent picture of the first-order regime of the model.

Explore related subjects

cond-mat.stat-mech

Keep this discovery

BibTeXRIS

D. Mataragkas, A. Vasilopoulos, Z. D. Vatansever, Y. Kim, D. -H. Kim, N. G Fytas. 2026-06-16. First-order phase transitions in the three-dimensional Blume-Capel ferromagnet. https://doi.org/10.1016/j.physa.2026.131922

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Universal sampling of spin systems across quenched disorder

Statistical physics extracts macroscopic laws by averaging over the many microscopic degrees of freedom of a system. Disordered systems demand a second and far harder average, one over the quenched randomness itself. The classic analytical routes, the replica and cavity methods, become uncontrolled outside mean-field or tree-like limits, and conventional numerical algorithms like parallel tempering require expensive, independent equilibration for every disorder realization. In this work, we introduce a universal neural variational framework that amortizes inference across the disorder ensemble, eliminating both the need for per-instance Markov chain equilibration and the cost of retraining instance-specific variational ansatzes. Built on an encoder-decoder Transformer architecture, after training once, it produces an explicit approximation to the Boltzmann distribution given previously unseen disorder realizations without further optimization. We validate this framework on 2D Edwards-Anderson models, and apply it to the random-bond Ising model, successfully capturing the Binder cumulant crossings near the Nishimori multicritical point. These results shift the object of variational inference from the single instance to the disorder ensemble, opening a route to frustrated many-body systems where instance-by-instance computation is prohibitive.

cond-mat.stat-mech↗
arXiv2026

Information-Theoretic Characterization of Macroscopic Chaos Emerging from the Chemical Master Equation

Open chemical reaction networks exhibit stochastic concentration dynamics at finite system sizes, whereas their macroscopic limit is governed by deterministic rate equations that can display chaos. In this Letter, we show theoretically that a rate of information loss constructed from two-time mutual information recovers the Kolmogorov-Sinai entropy in the deterministic limit. We verify this result through numerical simulations of a Markov jump process for a three-species system involving seven reactions.

cond-mat.stat-mech↗
arXiv2026

Orientational order on non-orientable domains

We study the statistical properties of passive and active many-body systems with orientational degrees of freedom on non-orientable domains. By rephrasing topological constraints as non-local symmetry relations on an orientable double-cover, we show that non-orientability eliminates global rotational soft modes without acting like an external field. In a passive XY model, this results in topological caging, where orientational fluctuations that exhibit conventional diffusive behavior on a torus saturate on a Klein bottle to a finite value that we compute exactly in the thermodynamic limit. In models of active self-propelled particles with orientational degrees of freedom, topological caging persists despite continuously changing interaction neighborhoods. In an active Ising spin model, non-orientability enforces the coexistence of ordered anti-parallel domains with vanishing global polar order, a state that is absent on orientable domains.

cond-mat.stat-mech↗