Efficient generation of series expansions for $\pm J$ Ising spin-glasses in a classical or a quantum (transverse) field
Abstract
We discuss generation of series expansions for Ising spin-glasses with a symmetric (i.e. bimodal) distribution on d-dimensional hypercubic lattices using linked-cluster methods. Simplifications for the bimodal distribution allow us to go to higher order than for a general distribution. We discuss two types of problem, one classical and one quantum. The classical problem is that of the Ising spin glass in a longitudinal magnetic field, , for which we obtain high temperature series expansions in variables and . The quantum problem is a study of the Ising spin glass in a transverse magnetic field for which we obtain a perturbation theory in powers of . These methods require (i) enumeration and counting of \textit{all} connected clusters that can be embedded in the lattice up to some order , and (ii) an evaluation of the contribution of each cluster for the quantity being calculated, known as the weight. We discuss a general method that takes the much smaller list (and count) of all no free-end (NFE) clusters on a lattice up to some order , and automatically generates all other clusters and their counts up to the same order. The weights for finite clusters in both cases have a simple graphical interpretation that allows us to proceed efficiently for a general configuration of the bonds, and at the end perform suitable disorder averaging. The order of our computations is limited by the weight calculations for the high-temperature expansions of the classical model, while they are limited by graph counting for the quantum system. Details of the calculational methods are presented.
Keywords
Cite
@article{arxiv.1709.03609,
title = {Efficient generation of series expansions for $\pm J$ Ising spin-glasses in a classical or a quantum (transverse) field},
author = {R. R. P. Singh and A. P. Young},
journal= {arXiv preprint arXiv:1709.03609},
year = {2018}
}
Comments
14 pages, 7 figures and 2 tables