On Long Range Ising Models with Random Boundary Conditions

Fuente: arXiv
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Main Authors: Endo, Eric O., van Enter, Aernout C. D., Ny, Arnaud Le
Format: Preprint
Published: 2024
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_version_ 1866917667602956288
author Endo, Eric O.
van Enter, Aernout C. D.
Ny, Arnaud Le
author_facet Endo, Eric O.
van Enter, Aernout C. D.
Ny, Arnaud Le
contents We consider polynomial long-range Ising models in one dimension, with ferromagnetic pair interactions decaying with power $2-α$ (for $0 \leq α< 1$), and prepared with randomly chosen boundary conditions. We show that at low temperatures in the thermodynamic limit the finite-volume Gibbs measures do not converge, but have a distributional limit, the so-called metastate. We find that there is a distinction between the values of $α$ less than or larger than $\frac{1}{2}$. For moderate, or intermediate, decay $α< \frac{1}{2}$, the metastate is very dispersed and supported on the set of all Gibbs measures, both extremal and non-extremal, whereas for slow decays $α> \frac{1}{2}$ the metastate is still dispersed, but has its support just on the set of the two extremal Gibbs measures, the plus measure and the minus measure. The former, moderate decays case, appears to be new and is due to the occurrence of almost sure boundedness of the random variable which is the sum of all interaction (free) energies between random and ordered half-lines, when the decay is fast enough, but still slow enough to get a phase transition ($α>0$); while the latter, slow decays case, is more reminiscent of and similar to the behaviour of higher-dimensional nearest-neighbour Ising models with diverging boundary (free) energies. We leave the threshold case $α=\frac{1}{2}$ for further studies.
format Preprint
id arxiv_https___arxiv_org_abs_2405_08374
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On Long Range Ising Models with Random Boundary Conditions
Endo, Eric O.
van Enter, Aernout C. D.
Ny, Arnaud Le
Mathematical Physics
Statistical Mechanics
Probability
60K35, 82B20
We consider polynomial long-range Ising models in one dimension, with ferromagnetic pair interactions decaying with power $2-α$ (for $0 \leq α< 1$), and prepared with randomly chosen boundary conditions. We show that at low temperatures in the thermodynamic limit the finite-volume Gibbs measures do not converge, but have a distributional limit, the so-called metastate. We find that there is a distinction between the values of $α$ less than or larger than $\frac{1}{2}$. For moderate, or intermediate, decay $α< \frac{1}{2}$, the metastate is very dispersed and supported on the set of all Gibbs measures, both extremal and non-extremal, whereas for slow decays $α> \frac{1}{2}$ the metastate is still dispersed, but has its support just on the set of the two extremal Gibbs measures, the plus measure and the minus measure. The former, moderate decays case, appears to be new and is due to the occurrence of almost sure boundedness of the random variable which is the sum of all interaction (free) energies between random and ordered half-lines, when the decay is fast enough, but still slow enough to get a phase transition ($α>0$); while the latter, slow decays case, is more reminiscent of and similar to the behaviour of higher-dimensional nearest-neighbour Ising models with diverging boundary (free) energies. We leave the threshold case $α=\frac{1}{2}$ for further studies.
title On Long Range Ising Models with Random Boundary Conditions
topic Mathematical Physics
Statistical Mechanics
Probability
60K35, 82B20
url https://arxiv.org/abs/2405.08374