• DOI:10.1103/PhysRevD.78.063544
• Corpus ID: 11322279

Nonperturbative quantum de Sitter universe

@article{Ambjorn2008NonperturbativeQD,
  title={Nonperturbative quantum de Sitter universe},
  author={Jan Ambjorn and Andrzej Goerlich and Jerzy Jurkiewicz and R. Loll},
  journal={Physical Review D},
  year={2008},
  volume={78},
  pages={063544}
}

• J. Ambjorn, A. Goerlich, +1 author R. Loll
• Published 28 July 2008
• Physics
• Physical Review D

The dynamical generation of a four-dimensional classical universe from nothing but fundamental quantum excitations at the Planck scale is a long-standing challenge to theoretical physicists. A candidate theory of quantum gravity which achieves this goal without invoking exotic ingredients or excessive fine-tuning is based on the nonperturbative and background-independent technique of causal dynamical triangulations. We demonstrate in detail how in this approach a macroscopic de Sitter universe, accompanied by small quantum fluctuations, emerges from the full gravitational path integral, and how the effective action determining its dynamics can be reconstructed uniquely from Monte Carlo data. We also provide evidence that it may be possible to penetrate to the sub-Planckian regime, where the Planck length is large compared to the lattice spacing of the underlying regularization of geometry.