Sommaire:

Approaching a critical point, the divergence of the correlation length of fluctuations can be cut-off by a confinement of the system. This truncation fosters finite size effects with universal features, such as the critical Casimir force which has particularly drawn attention in the past decades. I will describe how the critical Casimir force arises in confined critical systems and how its universality has led to a clear separation between numerical/theoretical approaches and experimental approaches. On the one hand, theoretical and numerical works on the subject have almost systematically been performed in magnetic model systems, such as the Ising or XY models. On the other hand, experimental approaches were all realized in fluid systems, such as binary mixtures or helium IV close to the superfluid transition. I will then present two very different numerical approaches, both intended to bridge this gap. Firstly, I will present a numerical test of an experimental protocol for measuring the critical Casimir force in a magnetic layer and, secondly, a numerical approach in a Lennard-Jones binary mixture. These approaches could open the way to a variety of experimental approaches in magnetic thin films and to studying fluctuations or out-of-equilibrium aspects of the Casimir force in simulations of fluids.

Pour plus d'informations, merci de contacter Berthier L.