Symmetry restoration, tunneling, and the null energy condition

A finite volume allows tunneling between degenerate vacua in quantum field theory, and leads to remarkable energetic features, arising from the competition of different saddle points partition function. We describe this for temperature at equilibrium, taking into account both static (Euclidean) time-dependent points. The effective theory homogeneous order parameter yields a nonextensive vacuum energy low temperatures, implying dynamical violation null condition.