ON THE TYPE OF THE TEMPERATURE PHASE TRANSITION IN O(N) MODELS

The temperature induced phase transition is investigated in the O(N) models by using graphics processing units (GPU) for Monte Carlo simulations on a lattice. General purpose computing on GPU (GPGPU) technology allows to collect a huge amount of data that gives a possibility to investigate the type of the phase transition for a wide interval of coupling values. It is found that for the small values of gimel a weak-first-order phase transition happens. It converts into a second order phase transition with the increase of gimel. A comparison with analytic calculations in continuum field theory and lattice simulations obtained by other authors is given.