GAUSSIAN, NON-GAUSSIAN CRITICAL FLUCTUATIONS IN THE CURIE-WEISS MODEL

It is known that at the critical temperature the Curie-Weiss mean-field model has non-Gaussian fluctuations and that ''internal fluctuations'' can be Gaussian. Here we compute the distribution of the q-mode magnetization fluctuations as a function of the temperature, the wave vector q, and a fading out external field. We obtain new classes of probability distributions generated by this external field as well as new critical behavior in terms of its rate of fading out. We discuss also the susceptibility as the limit q tending to zero.