Cosmological Landscape and Euclidean Quantum Gravity

Abstract

Quantum creation of the universe is described by the {\em density matrix} defined by the Euclidean path integral. This yields an ensemble of universes -- a cosmological landscape -- in a mixed quasi-thermal state which is shown to be dynamically more preferable than the pure quantum state of the Hartle-Hawking type. The latter is suppressed by the infinitely large positive action of its instanton, generated by the conformal anomaly of quantum matter. The Hartle-Hawking instantons can be regarded as posing initial conditions for Starobinsky solutions of the anomaly driven deSitter expansion, which are thus dynamically eliminated by infrared effects of quantum gravity. The resulting landscape of hot universes treated within the cosmological bootstrap (the self-consistent back reaction of quantum matter) turns out to be limited to a bounded range of the cosmological constant, which rules out a well-known infrared catastrophe of the vanishing cosmological constant and suggests an ultimate solution to the problem of unboundedness of the cosmological action in Euclidean quantum gravity.

6 pages, to be published in the Special issue of J. Phys. A dedicated to the Quantum Theories and Renormalization Group in Gravity and Cosmology (IRGAC 2006, Barcelona, Spain, 11-15 July 2006)

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Cited by in corpus (6)

• Why there is something rather than nothing (out of everything)?
• Quantum cosmology of a conformal multiverse
• Creation of entangled universes avoids the big bang singularity
• Third quantization: modeling the universe as a 'particle' in a quantum field theory of the minisuperspace
• What if? - Exploring the Multiverse through Euclidean wormholes
• Hydrogen-like Spectrum of Spontaneously Created Brane Universes with deSitter Ground State