Specific-Heat Exponent of Random-Field Systems via Ground-State Calculations
Abstract
Exact ground states of three-dimensional random field Ising magnets (RFIM) with Gaussian distribution of the disorder are calculated using graph-theoretical algorithms. Systems for different strengths h of the random fields and sizes up to N=96^3 are considered. By numerically differentiating the bond-energy with respect to h a specific-heat like quantity is obtained, which does not appear to diverge at the critical point but rather exhibits a cusp. We also consider the effect of a small uniform magnetic field, which allows us to calculate the T=0 susceptibility. From a finite-size scaling analysis, we obtain the critical exponents \nu=1.32(7), \alpha=-0.63(7), \eta=0.50(3) and find that the critical strength of the random field is h_c=2.28(1). We discuss the significance of the result that \alpha appears to be strongly negative.
Keywords
Cite
@article{arxiv.cond-mat/0105310,
title = {Specific-Heat Exponent of Random-Field Systems via Ground-State Calculations},
author = {A. K. Hartmann and A. P. Young},
journal= {arXiv preprint arXiv:cond-mat/0105310},
year = {2009}
}
Comments
9 pages, 9 figures, 1 table, revtex revised version, slightly extended