Out-of-equilibrium dynamics of large-N phi(4) QFT in finite volume - art. no. 025007

The lambda phi(4) model in a finite volume is studied in the infinite N Lim it both at equilibrium and out of equilibrium, with particular attention to certain fundamental features of the broken symmetry phase. The numerical s olution of the dynamical evolution equations shows that the zero-mode quant um fluctuations cannot grow macroscopically large starting from microscopic initial conditions. Thus we conclude that there is no evidence for a dynam ical Bose-Einstein condensation, in the usual sense. On the other hand, out of equilibrium the long-wavelength fluctuations do scale with the linear s ize of the system, signaling dynamical infrared properties quite different from the equilibrium ones characteristic of the same approximation scheme.