  We carry out numerical simulations to investigate spontaneous vortex
formation during a temperature quench of a superconductor film from the normal
to the superconducting phase in the absence of an external magnetic field. Our
results agree roughly with quantitative predictions of the flux trapping
scenario: In fast quenches the agreement is almost perfect, but there appears
to be some discrepancy in slower ones. In particular, our simulations
demonstrate the crucial role the electromagnetic field plays in this
phenomenon, making it very different from vortex formation in superfluids.
Besides superconductor experiments, our findings also shed more light on the
possible formation of cosmic defects in the early universe.
