Condensation of helium in aerogels as an experimental realization of the out-of-equilibrium Random Field Ising Model

Geoffroy Aubry (1) , Fabien Bonnet (1) , Mathieu Melich (1) , Laurent Guyon (1) , Panayotis Spathis (1) , Florence Despetis (2) , Pierre-Etienne Wolf (1)

1 NEEL - HELFA - Hélium : du fondamental aux applications
2 L2C - Laboratoire Charles Coulomb

The zero temperature out-of-equilibrium dynamics of the Random Field Ising Model has been predicted by Sethna et al. to present two regimes. While macroscopic magnetization loops are smooth above a critical disorder, they exhibit finite jumps below. Combining thermodynamic and optical measurements, we show that the condensation of 4He in base-catalysed silica aerogels of large porosity presents a similar out-of-equilibrium behavior when the temperature, rather than the disorder, is varied. Our experiment provides the first observation of the Sethna et al. theory in a non-magnetic system.

Mots clés: out-of-equilibrium phase transition; % liquid-vapor transition; disorder; Random Field Ising Model; % avalanches; hysteresis; helium; silica aerogel

Domaines: Systèmes désordonnés et réseaux de neurones [cond-mat.dis-nn]

Geoffroy Aubry, Fabien Bonnet, Mathieu Melich, Laurent Guyon, Panayotis Spathis, et al.. Condensation of helium in aerogels as an experimental realization of the out-of-equilibrium Random Field Ising Model. 2013. ⟨hal-00858215v1⟩