Using the remarkable mathematical construct of Eugene Wigner to visualize
quantum trajectories in phase space, quantum processes can be described in
terms of a quasi-probability distribution analogous to the phase space
probability distribution of the classical realm. In contrast to the incomplete
glimpse of the wave function that is achievable in a single shot experiment,
the Wigner distribution, accessible by quantum state tomography, reflects the
full quantum state. We show that during the fundamental symmetry-breaking
process of a generic quantum system - with a symmetry breaking field driving
the quantum system far from equilibrium - the Wigner distribution evolves
continuously with the system undergoing a sequence of revivals into the
symmetry unbroken state, followed by collapses onto a quasi-classical state
akin the one realised in infinite size systems. We show that generically this
state is completely delocalised both in momentum and in real space.Comment: 6 pages, 4 figure
