Evidence for a disorder driven phase transition in the condensation of   4He in aerogels
  We report on thermodynamic and optical measurements of the condensation process of $^4$He in three silica aerogels of different microstructures. For the two base-catalysed aerogels, the temperature dependence of the shape of adsorption isotherms and of the morphology of the condensation process show evidence of a disorder driven transition, in agreement with recent theoretical predictions. This transition is not observed for a neutral-catalysed aerogel, which we interpret as due to a larger disorder in this case. 
Fabien Bonnet (NEEL), Thierry Lambert (NEEL), Benjamin Cross (NEEL),   Laurent Guyon (NEEL), Florence Despetis (GES), Lauren...