PUB - Publikationen an der Universität Bielefeld

We investigate numerically the transverse and longitudinal correlation lengths of the three-dimensional 0(4) model as a function of the external field H. In the low-temperature phase we verify explicitly the H-1/2- dependence of the transverse correlation length, which is expected due to the Goldstone modes of the model. On the critical line we find the universal amplitude ratio epsilon(T)(c)/epsilon(L)(c) = 1.99(1). From our data we derive the universal scaling ftinction lot- the transverse correlation length. The H-dependencies of the correlation lengths in the high temperature phase are discussed and shown to be in accord with the scaling functions.