title: Critical behavior of the Ising model on the four-dimensional cubic lattice.
abstract: In this paper we investigate the nature of the singularity of the Ising model of the four-dimensional cubic lattice. It is rigorously known that the specific heat has critical exponent alpha=0 but a nonrigorous field-theory argument predicts an unbounded specific heat with a logarithmic singularity at Tc. We find that within the given accuracy the canonical ensemble data are consistent both with a logarithmic singularity and a bounded specific heat but that the microcanonical ensemble lends stronger support to a bounded specific heat. Our conclusion is that either much larger system sizes are needed for Monte Carlo studies of this model in four dimensions or the field-theory prediction of a logarithmic singularity is wrong.
authors.affiliation: Department of Theoretical Physics, KTH, SE-106 91 Stockholm, Sweden. phl@kth.se
authors.forename: P H
authors.initials: PH
authors.lastname: Lundow
authors.forename: K
authors.initials: K
authors.lastname: Markström