Baryogenesis, Domain Walls and the Role of Gravity

It has been recently speculated that global symmetries are broken by gravity. We propose a scenario for the generation of the baryon asymmetry in the early Universe in which the domain walls predicted by theories with discrete symmetries become unstable due to these Planck scale effects. The relative motion of the decaying walls can provide a mechanism for the departure from thermal equilibrium necessary to have a nonvanishing baryon asymmetry. In particular, we implement this idea within the frameworks of the Left-Right and Quark-Lepton symmetric models.