Universality and φ4 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 dimension 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 sharp) cutoff belong to the same universality class as those of the phi (4) lattice theory. Our analysis predicts both universal and nonuniversal Features of finite-size effects. and resolves long-standing discrepancies in earlier analyses of Monte Carlo (MC) data for the d = 5 Ising model. Our estimates of two fundamental length scales xi (o) and I-o are confirmed by very recent MC data.