We present a detailed numerical study of the elementary condensation events (avalanches) associated to the adsorption of 4He in silica aerogels. We use a coarse-grained lattice-gas description and determine the nonequilibrium behavior of the adsorbed gas within a local mean-field analysis, neglecting thermal fluctuations and activated processes. We investigate the statistical properties of the avalanches, such as their number, size and shape along the adsorption isotherms as a function of gel porosity, temperature, and chemical potential. Our calculations predict the existence of a line of critical points in the temperature-porosity diagram where the avalanche size distribution displays a power-law behavior and the adsorption isotherms have a universal scaling form. The estimated critical exponents seem compatible with those of the field-driven Random Field Ising Model at zero temperature.
@article{arxiv.cond-mat/0508267,
title = {Helium condensation in aerogel: avalanches and disorder-induced phase transition},
author = {F. Detcheverry and E. Kierlik and M. L. Rosinberg and G. Tarjus},
journal= {arXiv preprint arXiv:cond-mat/0508267},
year = {2009}
}