Symmetry Breaking with a Slant: Topological Defects after an Inhomogeneous Quench

We show that in second-order phase transformations that are induced by an inhomogeneous quench the density of topological defects is drastically suppressed as the velocity with which the quench propagates falls below a threshold velocity. This threshold is approximately given by the ratio of the healing length to relaxation time at freeze-out, which is the instant when the critical slowing down results in a transition from the adiabatic to the impulse behavior of the order parameter.