Abstract
Nelson Rei Bernardino: „Critical wetting transitions: A scientific soap opera?”
MPI für Metallforschung, Stuttgart
The theory of wetting transitions is well developed and can be considered an "almost" completely understood problem. By "almost" we are excluding the critical wetting transition in 3 dimensions for a fluid with short-range interactions, which after more than 20 years since the initial work still remains controversial.
The source of the problem is that d=3 is the upper critical dimension for wetting and the theory predicts that the transition shows strong nonuniversality. Experiments are notoriously difficult to perform but simulations by Binder, Landau and coworkers are in flagrant disagreement with theoretical predictions, observing only very weak deviations from mean-field behaviour.
Since the theory is based on a phenomenological interfacial Hamiltonian it has long been suspected that this could be the source of the problem. In the early 90s Fisher and Jin tried to build an interfacial Hamiltonian in a more systematic way. In a Hollywood-like twist they predicted that critical wetting should actually be a first-order transition!!!
In the latest episode of this scientific soap opera, a nonlocal interfacial Hamiltonian (developed to study wetting in non-planar substrates) showed interesting consequences for the wetting transition itself.
I will review the twists and turns of the theory of critical wetting and present the latest results on the Nonlocal Model. In particular I will show how the analysis of the two-point correlation function reveals an extra lengthscale, and provides an understanding of the physics behind the results of the Nonlocal Model.
If this is going to be the last episode of the critical wetting saga or if a new dramatic twist is just around the corner is anyone's guess.