Defect Formation Preempts Dynamical Symmetry Breaking in Closed Quantum   Systems
  We show that no matter how slowly a quantum-to-classical symmetry breaking process is driven, the adiabatic limit can never be reached in a macroscopic body. Massive defect formation preempts an adiabatic quantum-classical crossover and triggers the appearance of a symmetric non-equilibrium state that recursively collapses into the classical state, breaking the symmetry at punctured times. The presence of this state allows the quantum-classical transition to be investigated and controlled in mesoscopic devices by supplying externally the proper dynamical symmetry breaking perturbation. 
Carmine Ortix, Jorrit Rijnbeek and Jeroen van den Brink
quant-ph cond-mat.quant-gas