Spectral functions and dynamic critical behavior of relativistic Z2 theories

We investigate the dynamic critical behaviour of a relativistic scalar field theory with Z_2symmetry by calculating spectral functions of the order parameter at zero and non-vanishing momenta from first-principles classical-statistical lattice simulations in real-time. We find that at temperatures above the critical point (T > T_c) the spectral functions are well described by relativistic quasi-particle peaks. Close to the transition...