Formation of Topological Defects with Explicit Symmetry Breaking

We demonstrate a novel mechanism for topological defect formation in a first order phase transition for theories with small explicit symmetry breaking terms. We perform simulations of two bubble collisions in $2+1$ dimensions. In the coalesced region of bubble walls, field oscillations result in the production of a large number of vortices and antivortices. We discuss the implications of our results for axionic strings in the early Universe, for baryon formation in quark-gluon plasma, and for strings in liquid crystals in external electric or magnetic field.