Universality and phi(4) theory of finite-size effects above the upper critical dimension - art. no. 016113

We analyze finite-size effects in a L-d geometry above the upper critical d imension d=4 within the O(n) symmetric phi (4) theory on the basis of exact results for n-->infinity and one-loop results for n=1. We show that finite -size effects of the phi (4) continuum theory with a smooth (rather than sh arp) cutoff belong to the same universality class as those of the phi (4) l attice theory. Our analysis predicts both universal and nonuniversal Featur es of finite-size effects. and resolves long-standing discrepancies in earl ier analyses of Monte Carlo (MC) data for the d = 5 Ising model. Our estima tes of two fundamental length scales xi (o) and I-o are confirmed by very r ecent MC data.