The SelfOrganized de Sitter Universe
Abstract
We propose a theory of quantum gravity which formulates the quantum theory as a nonperturbative path integral, where each spacetime history appears with the weight exp(iS^{EH}), with S^{EH} the EinsteinHilbert action of the corresponding causal geometry. The path integral is diffeomorphisminvariant (only geometries appear) and backgroundindependent. The theory can be investigated by computer simulations, which show that a de Sitter universe emerges on large scales. This emergence is of an entropic, selforganizing nature, with the weight of the EinsteinHilbert action playing a minor role. Also, the quantum fluctuations around this de Sitter universe can be studied quantitatively and remain small until one gets close to the Planck scale. The structures found to describe Planckscale gravity are reminiscent of certain aspects of condensedmatter systems.
 Publication:

International Journal of Modern Physics D
 Pub Date:
 2008
 DOI:
 10.1142/S0218271808014011
 arXiv:
 arXiv:0806.0397
 Bibcode:
 2008IJMPD..17.2515A
 Keywords:

 Quantum gravity;
 nonperturbative;
 de Sitter universe;
 selforganization;
 General Relativity and Quantum Cosmology
 EPrint:
 Article unchanged, one line added to acknowledgment