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Title: Inflation and dark energy from the Brans-Dicke theory

Abstract

We consider the Brans-Dicke theory motivated by the f(R)=R+αR{sup n}−βR{sup 2−n} model to obtain a stable minimum of the Einstein frame scalar potential of the Brans-Dicke field. As a result we have obtained an inflationary scalar potential with non-zero value of residual vacuum energy, which may be a source of dark energy. In addition we discuss the probability of quantum tunnelling from the minimum of the potential. Our results can be easily consistent with PLANCK or BICEP2 data for appropriate choices of the value of n and ω.

Authors:
 [1]; ;  [2]
  1. Institute of Physics, Jagiellonian UniversityŁojasiewicza 11, 30-348 Kraków (Poland)
  2. Institute of Theoretical Physics, Faculty of Physics, University of Warsawul. Pasteura 5, 02-093 Warszawa (Poland)
Publication Date:
Sponsoring Org.:
SCOAP3, CERN, Geneva (Switzerland)
OSTI Identifier:
22454561
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 06; Other Information: PUBLISHER-ID: JCAP06(2015)031; OAI: oai:repo.scoap3.org:10792; 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)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BRANES; COSMOLOGICAL INFLATION; EINSTEIN FIELD EQUATIONS; GRAVITATION; NONLUMINOUS MATTER; TUNNEL EFFECT

Citation Formats

Artymowski, Michał, Lalak, Zygmunt, and Lewicki, Marek. Inflation and dark energy from the Brans-Dicke theory. United States: N. p., 2015. Web. doi:10.1088/1475-7516/2015/06/031.
Artymowski, Michał, Lalak, Zygmunt, & Lewicki, Marek. Inflation and dark energy from the Brans-Dicke theory. United States. doi:10.1088/1475-7516/2015/06/031.
Artymowski, Michał, Lalak, Zygmunt, and Lewicki, Marek. 2015. "Inflation and dark energy from the Brans-Dicke theory". United States. doi:10.1088/1475-7516/2015/06/031.
@article{osti_22454561,
title = {Inflation and dark energy from the Brans-Dicke theory},
author = {Artymowski, Michał and Lalak, Zygmunt and Lewicki, Marek},
abstractNote = {We consider the Brans-Dicke theory motivated by the f(R)=R+αR{sup n}−βR{sup 2−n} model to obtain a stable minimum of the Einstein frame scalar potential of the Brans-Dicke field. As a result we have obtained an inflationary scalar potential with non-zero value of residual vacuum energy, which may be a source of dark energy. In addition we discuss the probability of quantum tunnelling from the minimum of the potential. Our results can be easily consistent with PLANCK or BICEP2 data for appropriate choices of the value of n and ω.},
doi = {10.1088/1475-7516/2015/06/031},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 06,
volume = 2015,
place = {United States},
year = 2015,
month = 6
}
  • We consider the Brans-Dicke theory motivated by the f(R) = R + α R{sup n} − β R{sup 2−n} model to obtain a stable minimum of the Einstein frame scalar potential of the Brans-Dicke field. As a result we have obtained an inflationary scalar potential with non-zero value of residual vacuum energy, which may be a source of dark energy. In addition we discuss the probability of quantum tunnelling from the minimum of the potential. Our results can be easily consistent with PLANCK or BICEP2 data for appropriate choices of the value of n and ω.
  • We consider the possibility that the discrepancy between the dynamical estimate of the density of matter in the Universe {Omega}{approx}0.2 and the prediction of inflation {Omega}=1 can be accounted for by oscillation of the Brans-Dicke scalar of the simplest extended inflation model. It is shown that such an explanation requires an extremely small self-coupling for the Brans-Dicke scalar ({lambda}{lt}10{sup {minus}60}) as well as an apparent fine-tuning of the initial amplitude of the Brans-Dicke scalar at the end of inflation, which may however be understood by the anthropic principle. The requirement that the anisotropies of the cosmic microwave background radiation inducedmore » by quantum fluctuations of the Brans-Dicke field during inflation are acceptably small constrains the coupling of the Brans-Dicke scalar to the Ricci scalar to be not much greater than {similar to}0.01, which is close to the lower limit allowed in the simplest extended inflation model. It is also shown that if one imposes the constraint that the spatial fluctuations of the Brans-Dicke scalar induced by bubble growth during the first-order phase transition do not give too large a contribution to the energy density at present, then the frequency of the oscillations has an upper bound, which is typically {similar to}10{sup 6} GHz. This significantly reduces the range of frequencies allowed, which would otherwise have an upper bound {similar to}10{sup 12} GHz coming from the stability of the Brans-Dicke oscillations, while leaving a range of frequencies above the {similar to}1 GHz observational limit coming from terrestrial experiments designed to observe deviations from Newtonian gravity. Thus the constraints from spatially varying fluctuations of the Brans-Dicke scalar do not rule out the model.« less
  • We study an intermediate inflationary stage in a Jordan-Brans-Dicke theory. In this scenario we analyze the quantum fluctuations corresponding to adiabatic and isocurvature modes. Our model is compared to that described by using the intermediate model in Einstein general relativity theory. We assess the status of this model in light of the seven-year WMAP data.
  • We construct a cosmological model of late acceleration based on the new agegraphic dark energy model in the framework of Brans-Dicke cosmology where the new agegraphic energy density {rho}{sub D}=3n{sup 2}m{sub p}{sup 2}/{eta}{sup 2} is replaced with {rho}{sub D}=3n{sup 2{phi}2}/(4{omega}{eta}{sup 2}). We show that the combination of the Brans-Dicke field and agegraphic dark energy can accommodate a w{sub D}=-1 crossing for the equation of state of noninteracting dark energy. When an interaction between dark energy and dark matter is taken into account, the transition of w{sub D} to the phantom regime can be more easily accounted for than when wemore » resort to the Einstein field equations. In the limiting case {alpha}=0 ({omega}{yields}{infinity}), all previous results of the new agegraphic dark energy in Einstein gravity are restored.« less
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