The Thermodynamic Limit of Spin Systems on Random Graphs

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Searle, Amy, Tindall, Joseph
Format: Preprint
Published: 2023
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866909074354864128
author Searle, Amy
Tindall, Joseph
author_facet Searle, Amy
Tindall, Joseph
contents We utilise the graphon--a continuous mathematical object which represents the limit of convergent sequences of dense graphs--to formulate a general, continuous description of quantum spin systems in thermal equilibrium when the average co-ordination number grows extensively in the system size. Specifically, we derive a closed set of coupled non-linear Fredholm integral equations which govern the properties of the system. The graphon forms the kernel of these equations and their solution yields exact expressions for the macroscopic observables in the system in the thermodynamic limit. We analyse these equations for both quantum and classical spin systems, recovering known results and providing novel analytical solutions for a range of more complex cases. We supplement this with controlled, finite-size numerical calculations using Monte-Carlo and Tensor Network methods, showing their convergence towards our analytical results with increasing system size.
format Preprint
id arxiv_https___arxiv_org_abs_2303_00731
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle The Thermodynamic Limit of Spin Systems on Random Graphs
Searle, Amy
Tindall, Joseph
Statistical Mechanics
Quantum Physics
We utilise the graphon--a continuous mathematical object which represents the limit of convergent sequences of dense graphs--to formulate a general, continuous description of quantum spin systems in thermal equilibrium when the average co-ordination number grows extensively in the system size. Specifically, we derive a closed set of coupled non-linear Fredholm integral equations which govern the properties of the system. The graphon forms the kernel of these equations and their solution yields exact expressions for the macroscopic observables in the system in the thermodynamic limit. We analyse these equations for both quantum and classical spin systems, recovering known results and providing novel analytical solutions for a range of more complex cases. We supplement this with controlled, finite-size numerical calculations using Monte-Carlo and Tensor Network methods, showing their convergence towards our analytical results with increasing system size.
title The Thermodynamic Limit of Spin Systems on Random Graphs
topic Statistical Mechanics
Quantum Physics
url https://arxiv.org/abs/2303.00731