  We discuss the recent scenario of tachyonic preheating at the end of
inflation as a consequence of a tachyonic mass term in the scalar field
responsible for spontaneous symmetry breaking. We use 3D lattice simulations to
expore this very non-perturbative and non-linear phenomenon, which occurs due
to the spinodal instability of the scalar field. Tachyonic preheating is so
efficient that symmetry breaking typically completes within a single
oscillation of the field distribution as it rolls towards the minimum of its
effective potential.
