EXACT FUNCTIONAL RENORMALIZATION-GROUP FOR WETTING TRANSITIONS IN 1 + 1 DIMENSIONS

Using an exact functional renormalization group (RG), we study wetting transitions in d = 1 + 1 dimensions. This RG acts in the function space of the interaction potentials for two interfaces. The RG flow exhibits i) a whole line of fixed points and ii), a separatrix which represents an analytic continuation of the fixed-point line. Numerical and analytical work shows that the line of fixed points almost forms a closed loop in function space. The separatrix, on the other hand, describes a subregime where the wetting transitions are first-order but have unusual scaling properties. A generalization of the RG indicates that these unusual transitions are replaced by usual first-order transitions in d # 1 + 1. © 1990 IOP Publishing Ltd.