Exact zeros of the partition function for a continuum system with double gaussian peaks
We calculate the exact zeros of the partition function for a continuum system where the probability distribution for the order parameter is given by two asymmetric Gaussian peaks. When the positions of the two peaks coincide, the two separate loci of the zeros that used to give a first-order transition touch each other, with the density of zeros vanishing at the contact point on the positive real axis. Instead of the second-order transition of the Ehrenfest classification as one might naively expect, one finds a critical behavior in this limit.
Lee
J
Institute of Physics, University of Tokyo, Komaba, Meguro-ku, Tokyo 153, Japan.
Lee
KC