Equidistant versus bipartite ground states for 1D classical fluids at fixed particle density

Fuente: arXiv
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Main Authors: Bétermin, Laurent, Šamaj, Ladislav, Travěnec, Igor
Format: Preprint
Published: 2025
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author Bétermin, Laurent
Šamaj, Ladislav
Travěnec, Igor
author_facet Bétermin, Laurent
Šamaj, Ladislav
Travěnec, Igor
contents We study the ground-state properties of one-dimensional fluids of classical (i.e., non-quantum) particles interacting pairwisely via a potential, at the fixed particle density $ρ$. Restricting ourselves to periodic configurations of particles, two possibilities are considered: an equidistant chain of particles with the uniform spacing $A=1/ρ$ and its simplest non-Bravais modulation, namely a bipartite lattice composed of two equidistant chains, shifted with respect to one another. Assuming the long range of the interaction potential, the equidistant chain dominates if $A$ is small enough, $0<A<A_c$. At a critical value of $A=A_c$, the system undergoes a continuous second-order phase transition from the equidistant chain to a bipartite lattice. The energy and the order parameter are singular functions of the deviation from the critical point $A-A_c$ with universal (i.e., independent of the model's parameters) mean-field values of critical exponents. The tricritical point at which the curve of continuous second-order transitions meets with the one of discontinuous first-order transitions is determined. The general theory is applied to the Lennard-Jones model with the $(n,m)$ Mie potential for which the phase diagram is constructed. The inclusion of a hard-core around each particle reveals a non-universal critical phenomenon with an $m$-dependent critical exponent.
format Preprint
id arxiv_https___arxiv_org_abs_2502_16639
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Equidistant versus bipartite ground states for 1D classical fluids at fixed particle density
Bétermin, Laurent
Šamaj, Ladislav
Travěnec, Igor
Mathematical Physics
74G65, 74N05, 82B26
We study the ground-state properties of one-dimensional fluids of classical (i.e., non-quantum) particles interacting pairwisely via a potential, at the fixed particle density $ρ$. Restricting ourselves to periodic configurations of particles, two possibilities are considered: an equidistant chain of particles with the uniform spacing $A=1/ρ$ and its simplest non-Bravais modulation, namely a bipartite lattice composed of two equidistant chains, shifted with respect to one another. Assuming the long range of the interaction potential, the equidistant chain dominates if $A$ is small enough, $0<A<A_c$. At a critical value of $A=A_c$, the system undergoes a continuous second-order phase transition from the equidistant chain to a bipartite lattice. The energy and the order parameter are singular functions of the deviation from the critical point $A-A_c$ with universal (i.e., independent of the model's parameters) mean-field values of critical exponents. The tricritical point at which the curve of continuous second-order transitions meets with the one of discontinuous first-order transitions is determined. The general theory is applied to the Lennard-Jones model with the $(n,m)$ Mie potential for which the phase diagram is constructed. The inclusion of a hard-core around each particle reveals a non-universal critical phenomenon with an $m$-dependent critical exponent.
title Equidistant versus bipartite ground states for 1D classical fluids at fixed particle density
topic Mathematical Physics
74G65, 74N05, 82B26
url https://arxiv.org/abs/2502.16639