Born Again Universe

Understand

We present a class of nonsingular, bouncing cosmologies that evade singularity theorems through the use of vorticity in compact extra dimensions.

• The vorticity combats the focusing of geodesics during the contracting phase.
• The construction requires fluids that violate the null energy condition (NEC) in the compact dimensions, where they can be provided by known stable NEC violating sources such as Casimir energy.
• The four dimensional effective theory contains an NEC violating fluid of Kaluza-Klein excitations of the higher dimensional metric.