SELF-CREATING BRANE WORLDS

Abstract

Several boundary conditions for the universe have been hitherto suggested, basing on different philosophical approaches. In particular, one may choose between the notions that the universe was created either from nothing or by itself. The quantum state of a universe created from nothing has been already formulated under distinct standpoints by Hartle, Hawking, Vilenkin and others. In this paper we have concentrated on deriving a quantum theory for a self-created universe. Thus, we have first considered the spacetime structure of a six-dimensional de Sitter space with a multiply connected region and, by using a cutting and pasting procedure, we have then been able to show that one can introduce a four-brane in such a spacetime whose evolution can also be considered within the context of ekpyrotic and cyclic universes, and quantized in terms of the sum-over-histories formulation, according to the rules of the generalized quantum theory developed by Hartle.