Boom and bust inflation: a graceful exit via compact extra dimensions.
A model of inflation is proposed in which compact extra dimensions allow a graceful exit without recourse to flat potentials or super-Planckian field values. Though bubbles of true vacuum are too sparse to uniformly reheat the Universe by colliding with each other, a compact dimension enables a single bubble to uniformly reheat by colliding with itself. This mechanism, which generates an approximately scale invariant perturbation spectrum, requires that inflation be driven by a bulk field, that vacuum decay be slow, and that the extra dimension be at least a hundred times larger than the false vacuum Hubble length.
Brown
Adam R
AR
Physics Department, Columbia University, New York, New York 10027, USA. adam@phys.columbia.edu