The Annihilation of Two Phase Interfaces in Superfluid He-3: Simulated Brane Annihilation in the Laboratory.

The structure of the order parameter in superfluid He-3 mimics closely the analogous structure of the "metric" of the Universe. Since the superfluid may exist in several phases we can, using a magnetic field gradient, set up coherent phase boundaries in the superfluid which are the closest laboratory analogues we have to cosmological branes. We find that if we annihilate two such branes (an AB and a BA interface) then we find that the annihilation leaves relic defects in the superfluid texture. These results can help to "validate" those braneworld scenarios where brane annihilation is thought similarly to lead to the formation of topological defects such as cosmic strings