Renormalization group and variational treatments for a d-dimensional sine-Gordon model with correlated random fields

We study the effects of correlated symmetry-breaking-like random fields on critical properties of a d-dimensional sine-Gordon model. A Wilsonian renor malization group analysis shows an unusual scenario in the absence of stabl e fixed points. The physical nature of the related runaway in the parameter space is investigated by means of a complementary variational treatment. S elf-consistent predictions for d > 1 suggest that the disorder of the type considered here inhibits any phase transition with diverging correlation le ngth and that the system lives in a "glassy-phase" at all temperatures. (C) 1999 Elsevier Science B.V. All rights reserved.