Defect formulation in quantum field theory

We propose a quantum approach to nonequilibrium dynamics which combine s the successful aspects of classical-statistical simulations on a lattice with the ability to take into account quantum corrections. It is based on the 2PI effective action for inhomogeneous fields and a volume average. This procedure does not involve any double counting which could appear in sampling prescriptions fo r inhomogeneous quantum evolutions. As an example, we study nonequilibrium dynamics of defect formation in 1+1 dimensional relativistic scalar field theory an d compare to insufficient descriptions based on homogeneous quantum fields.