Universal Magnetic Fluctuations with a Field Induced Length Scale
Abstract
We calculate the probability density function for the order parameter fluctuations in the low temperature phase of the 2D-XY model of magnetism near the line of critical points. A finite correlation length, \xi, is introduced with a small magnetic field, h, and an accurate expression for \xi(h) is developed by treating non-linear contributions to the field energy using a Hartree approximation. We find analytically a series of universal non-Gaussian distributions with a finite size scaling form and present a Gumbel-like function that gives the PDF to an excellent approximation. We propose the Gumbel exponent, a(h), as an indirect measure of the length scale of correlations in a wide range of complex systems.
Cite
@article{arxiv.cond-mat/0102283,
title = {Universal Magnetic Fluctuations with a Field Induced Length Scale},
author = {B. Portelli and P. C. W. Holdsworth and M. Sellitto and S. T. Bramwell},
journal= {arXiv preprint arXiv:cond-mat/0102283},
year = {2009}
}
Comments
7 pages, 4 figures, 1 table. To appear in Phys. Rev. E