Interface Localization-Delocalization in a Double Wedge: A New Universality Class with Strong Fluctuations and Anisotropic Scaling

Using Monte Carlo simulations and finite-size scaling methods we study ``wetting'' in Ising systems in a L×L×Ly pore with quadratic cross section. Antisymmetric surface fields Hₛ act on the free L×Ly surfaces of the opposing wedges, and periodic boundary conditions are applied along the y direction. In the limit L→∞, Ly/L³=const, the system exhibits a new type of phase transition, which is the analog of the ``filling transition'' that occurs in a single wedge. It is characterized by critical exponents α=3/4, β=0, and γ=5/4 for the specific heat, order parameter, and susceptibility, respectively.