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Title: Galilean creation of the inflationary universe

It has been pointed out that the null energy condition can be violated stably in some non-canonical scalar-field theories. This allows us to consider the Galilean Genesis scenario in which the universe starts expanding from Minkowski spacetime and hence is free from the initial singularity. We use this scenario to study the early-time completion of inflation, pushing forward the recent idea of Pirtskhalava et al. We present a generic form of the Lagrangian governing the background and perturbation dynamics in the Genesis phase, the subsequent inflationary phase, and the graceful exit from inflation, as opposed to employing the effective field theory approach. Our Lagrangian belongs to a more general class of scalar-tensor theories than the Horndeski theory and Gleyzes-Langlois-Piazza-Vernizzi generalization, but still has the same number of the propagating degrees of freedom, and thus can avoid Ostrogradski instabilities. We investigate the generation and evolution of primordial perturbations in this scenario and show that one can indeed construct a stable model of inflation preceded by (generalized) Galilean Genesis.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Department of Physics, Rikkyo University,Toshima, Tokyo 175-8501 (Japan)
  2. Department of Physics, Tokyo Institute of Technology,Tokyo 152-8551 (Japan)
  3. Research Center for the Early Universe (RESCEU),Graduate School of Science, The University of Tokyo,Tokyo 113-0033 (Japan)
  4. (Japan)
  5. (Kavli IPMU),UTIAS, WPI, The University of Tokyo,Kashiwa, Chiba 277-8568 (Japan)
Publication Date:
OSTI Identifier:
22454567
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 07; Other Information: PUBLISHER-ID: JCAP07(2015)017; OAI: oai:repo.scoap3.org:11063; Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA)
Sponsoring Org:
SCOAP3, CERN, Geneva (Switzerland)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; DEGREES OF FREEDOM; FIELD THEORIES; GALACTIC EVOLUTION; INFLATIONARY UNIVERSE; LAGRANGIAN FUNCTION; ORIGIN; PERTURBATION THEORY; SCALAR FIELDS; SINGULARITY