Eur. Phys. J. B (2012) 85: 349
https://doi.org/10.1140/epjb/e2012-30731-8

Regular Article

Universality aspects of the trimodal random-field Ising model

¹ Departamento de Física Teórica I, Universidad Complutense, 28040 Madrid, Spain
² Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
³ Institute for Theoretical Physics and Center for Computational Materials Science, Vienna University of Technology, Hauptstraße 8-10, 1040 Vienna, Austria
⁴ Vienna Computational Materials Laboratory, Sensengasse 8/12, 1090 Vienna, Austria

^a e-mail: nfytas@phys.uoa.gr

Received: 7 August 2012
Received in final form: 9 September 2012
Published online: 18 October 2012

Abstract

We investigate the critical properties of the d = 3 random-field Ising model with an equal-weight trimodal distribution at zero temperature. By implementing suitable graph-theoretical algorithms, we compute large ensembles of ground states for several values of the disorder strength h and system sizes up to N = 128³. Using a new approach based on the sample-to-sample fluctuations of the order parameter of the system and proper finite-size scaling techniques we estimate the critical disorder strength h_c = 2.747(3) and the critical exponents of the correlation length ν = 1.34(6) and order parameter β = 0.016(4). These estimates place the model into the universality class of the corresponding Gaussian random-field Ising model.