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Title: Emergent cosmology revisited

Abstract

We explore the possibility of emergent cosmology using the effective potential formalism. We discover new models of emergent cosmology which satisfy the constraints posed by the cosmic microwave background (CMB). We demonstrate that, within the framework of modified gravity, the emergent scenario can arise in a universe which is spatially open/closed. By contrast, in general relativity (GR) emergent cosmology arises from a spatially closed past-eternal Einstein Static Universe (ESU). In GR the ESU is unstable, which creates fine tuning problems for emergent cosmology. However, modified gravity models including Braneworld models, Loop Quantum Cosmology (LQC) and Asymptotically Free Gravity result in a stable ESU. Consequently, in these models emergent cosmology arises from a larger class of initial conditions including those in which the universe eternally oscillates about the ESU fixed point. We demonstrate that such an oscillating universe is necessarily accompanied by graviton production. For a large region in parameter space graviton production is enhanced through a parametric resonance, casting serious doubts as to whether this emergent scenario can be past-eternal.

Authors:
;  [1];  [2];  [3]
  1. Inter-University Centre for Astronomy and Astrophysics, Pune 411007 (India)
  2. Bogolyubov Institute for Theoretical Physics, Kiev 03680 (Ukraine)
  3. Department of Physics, The LNM Institute of Information Technology, Jaipur 302031 (India)
Publication Date:
OSTI Identifier:
22373453
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2014; Journal Issue: 07; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BRANES; GENERAL RELATIVITY THEORY; GRAVITATION; M-THEORY; POTENTIALS; QUANTUM COSMOLOGY; RELICT RADIATION; SPACE; UNIVERSE

Citation Formats

Bag, Satadru, Sahni, Varun, Shtanov, Yuri, and Unnikrishnan, Sanil, E-mail: satadru@iucaa.ernet.in, E-mail: varun@iucaa.ernet.in, E-mail: shtanov@bitp.kiev.ua, E-mail: sanil@lnmiit.ac.in. Emergent cosmology revisited. United States: N. p., 2014. Web. doi:10.1088/1475-7516/2014/07/034.
Bag, Satadru, Sahni, Varun, Shtanov, Yuri, & Unnikrishnan, Sanil, E-mail: satadru@iucaa.ernet.in, E-mail: varun@iucaa.ernet.in, E-mail: shtanov@bitp.kiev.ua, E-mail: sanil@lnmiit.ac.in. Emergent cosmology revisited. United States. doi:10.1088/1475-7516/2014/07/034.
Bag, Satadru, Sahni, Varun, Shtanov, Yuri, and Unnikrishnan, Sanil, E-mail: satadru@iucaa.ernet.in, E-mail: varun@iucaa.ernet.in, E-mail: shtanov@bitp.kiev.ua, E-mail: sanil@lnmiit.ac.in. Tue . "Emergent cosmology revisited". United States. doi:10.1088/1475-7516/2014/07/034.
@article{osti_22373453,
title = {Emergent cosmology revisited},
author = {Bag, Satadru and Sahni, Varun and Shtanov, Yuri and Unnikrishnan, Sanil, E-mail: satadru@iucaa.ernet.in, E-mail: varun@iucaa.ernet.in, E-mail: shtanov@bitp.kiev.ua, E-mail: sanil@lnmiit.ac.in},
abstractNote = {We explore the possibility of emergent cosmology using the effective potential formalism. We discover new models of emergent cosmology which satisfy the constraints posed by the cosmic microwave background (CMB). We demonstrate that, within the framework of modified gravity, the emergent scenario can arise in a universe which is spatially open/closed. By contrast, in general relativity (GR) emergent cosmology arises from a spatially closed past-eternal Einstein Static Universe (ESU). In GR the ESU is unstable, which creates fine tuning problems for emergent cosmology. However, modified gravity models including Braneworld models, Loop Quantum Cosmology (LQC) and Asymptotically Free Gravity result in a stable ESU. Consequently, in these models emergent cosmology arises from a larger class of initial conditions including those in which the universe eternally oscillates about the ESU fixed point. We demonstrate that such an oscillating universe is necessarily accompanied by graviton production. For a large region in parameter space graviton production is enhanced through a parametric resonance, casting serious doubts as to whether this emergent scenario can be past-eternal.},
doi = {10.1088/1475-7516/2014/07/034},
journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 07,
volume = 2014,
place = {United States},
year = {2014},
month = {7}
}