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Weakly first-order transition in an athermal lattice gas
1Dipartimento di Ingegneria, Università degli Studi della Campania "Luigi Vanvitelli", Via Roma 29, 81031 Aversa, Italy and The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy.
Physical Review. E
|June 16, 2022
Summary
This study reveals a weakly first-order phase transition in a 2D lattice gas model. Despite apparent discontinuities, analysis shows size-dependent thermal exponents, reconciling paradoxical observations in particle density and entropy.
Area of Science:
- Statistical Mechanics
- Condensed Matter Physics
- Computational Physics
Background:
- Understanding phase transitions in low-dimensional systems is crucial.
- Athermal lattice gas models provide insights into collective particle behavior.
- Investigating constraints on particle interactions reveals novel phase behaviors.
Purpose of the Study:
- To determine the phase behavior of a 2D athermal lattice gas with specific nearest-neighbor constraints.
- To identify the ground state and close packing density.
- To reconcile paradoxical thermodynamic observations near a phase transition.
Main Methods:
- Simulation of a two-dimensional athermal lattice gas on a square lattice.
- Analysis of ground state and close packing density.
- Phenomenological renormalization and curve-crossing methods to analyze size-dependent thermal exponents.
Main Results:
- The model exhibits an ordering phase transition at large chemical potential with sublattice occupation.
- Apparent discontinuities in particle density and entropy were observed near the transition.
- Order parameter and thermodynamic fluctuations did not scale with system volume, indicating non-standard behavior.
Conclusions:
- The observed phenomena are reconciled by identifying a weakly first-order phase transition.
- Size-dependent analysis of thermal exponents is key to understanding the transition.
- The study highlights the complexity of phase transitions in constrained lattice gas systems.
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