Coincidence Problem in an Oscillating Universe
Guangcan Yang,Anzhong Wang +1 more
TLDR
In this paper, an oscillating universe model in brane world scenario was analyzed and it was shown that the period of the universe is not sensitive to tension of the brane, but sensitive to the equation-of-state parameter $w$ of the phantom dark energy.Abstract:
We analyze an oscillating universe model in brane world scenario. The oscillating universe cycles through a series of expansions and contractions and its energy density is dominated by dust matter at early-time expansion phase and by phantom dark energy at late-time expansion phase. We find that the period of the oscillating universe is not sensitive to the tension of the brane, but sensitive to the equation-of-state parameter $w$ of the phantom dark energy, and the ratio of the period to the current Hubble age approximately varies from 3 to 9 when the parameter $w$ changes from -1.4 to -1.1. The fraction of time that the oscillating universe spends in the coincidence state is also comparable to the period of the oscillating universe. This result indicates that the coincidence problem can be significantly ameliorated in the oscillating universe without singularity.read more
Citations
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$w_d=-1$ in interacting quintessence model
TL;DR: In this paper, a model consisting of a quintessence scalar field interacting with cold dark matter is considered and conditions required to reach $w_d=-1$ are discussed, and it is shown that reaching the phantom divide line puts some constraints on the interaction between dark energy and dark matter.
Journal ArticleDOI
Dark-energy dynamics required to solve the cosmic coincidence
TL;DR: In this paper, the authors explore the coincidence problem in dynamic dark-energy models using the temporal distribution of terrestrial-planet bound observers and find that any realistic DDE model which can be parametrized as $w={w}_{0}+{w}-a}(1\ensuremath{-}a)$ over a few e-folds has a significant fraction of observers in the universe.
Journal ArticleDOI
Anthropic versus cosmological solutions to the coincidence problem
A. Barreira,P. P. Avelino +1 more
TL;DR: In this article, the authors investigated possible solutions to the coincidence problem in flat phantom dark energy models with a constant dark-energy equation of state and quintessence model with a linear scalar field potential.
Journal ArticleDOI
Fractional action oscillating phantom cosmology with conformal coupling
TL;DR: In this article, the late-time dynamics of a flat Friedmann-Robertson Walker universe in the context of a non-minimal fractional cosmology characterized by fractional weight in time was studied.
Journal ArticleDOI
Inhomogeneous dark energy and cosmological acceleration
TL;DR: In this article, the evolution of an inhomogeneous fluid with self-similarity of the second kind and anisotropic pressure was studied and a class of solution to the Einstein field equations by assuming an equation of state where the radial pressure of the fluid is proportional to its energy density and that the fluid moves along time-like geodesics.
References
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Measurements of Omega and Lambda from 42 High-Redshift Supernovae
Saul Perlmutter,Saul Perlmutter,Greg Aldering,Gerson Goldhaber,Gerson Goldhaber,R. A. Knop,Peter Nugent,P. G. Castro,P. G. Castro,Susana E. Deustua,Sebastien Fabbro,Sebastien Fabbro,A. Goobar,A. Goobar,Donald E. Groom,I. M. Hook,I. M. Hook,A. G. Kim,A. G. Kim,A. G. Kim,M. Y. Kim,Julia C. Lee,Julia C. Lee,Nelson J. Nunes,Nelson J. Nunes,Reynald Pain,Reynald Pain,C. R. Pennypacker,C. R. Pennypacker,Robert Quimby,Christopher Lidman,Richard S. Ellis,Mike Irwin,Richard G. McMahon,Pilar Ruiz-Lapuente,Nicholas A. Walton,Bradley E. Schaefer,B. J. Boyle,Alexei V. Filippenko,Thomas Matheson,A. S. Fruchter,Nino Panagia,Nino Panagia,Heidi Jo Newberg,Warrick J. Couch +44 more
TL;DR: In this paper, the mass density, Omega_M, and cosmological-constant energy density of the universe were measured using the analysis of 42 Type Ia supernovae discovered by the Supernova Cosmology project.
Journal ArticleDOI
Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
Adam G. Riess,Alexei V. Filippenko,Peter Challis,Alejandro Clocchiatti,Alan H. Diercks,Peter M. Garnavich,R. L. Gilliland,Craig J. Hogan,Saurabh Jha,Robert P. Kirshner,Bruno Leibundgut,Mark M. Phillips,David J Reiss,Brian P. Schmidt,R. A. Schommer,R. Chris Smith,R. Chris Smith,Jason Spyromilio,Christopher W. Stubbs,Nicholas B. Suntzeff,John L. Tonry +20 more
TL;DR: In this article, the authors used spectral and photometric observations of 10 Type Ia supernovae (SNe Ia) in the redshift range 0.16 " z " 0.62.
Journal ArticleDOI
Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
Adam G. Riess,Alexei V. Filippenko,Peter Challis,Alejandro Clocchiattia,Alan H. Diercks,Peter M. Garnavich,R. L. Gilliland,Craig J. Hogan,Saurabh Jha,Robert P. Kirshner,Bruno Leibundgut,Mark M. Phillips,David J Reiss,Brian P. Schmidt,Robert A. Schommer,R. Chris Smith,Jason Spyromilio,Christopher W. Stubbs,Nicholas B. Suntzeff,John L. Tonry +19 more
TL;DR: In this paper, the authors present observations of 10 type Ia supernovae (SNe Ia) between 0.16 0 and 4.0 sigma confidence levels, for two fitting methods respectively.
Journal ArticleDOI
Measurements of Omega and Lambda from 42 High-Redshift Supernovae
Saul Perlmutter,Greg Aldering,G. Goldhaber,R. A. Knop,Peter Nugent,P. G. Castro,Susana E. Deustua,Sebastien Fabbro,A. Goobar,D. E. Groom,I. M. Hook,A. G. Kim,M. Y. Kim,Julia C. Lee,Nelson J. Nunes,Reynald Pain,C. R. Pennypacker,R. M. Quimby,C. Lidman,Richard S. Ellis,Michael G. Irwin,Richard G. McMahon,P. Ruiz-Lapuente,Nicholas A. Walton,Bradley E. Schaefer,B. J. Boyle,Alexei V. Filippenko,Thomas Matheson,A. S. Fruchter,Nino Panagia,Heidi Jo Newberg,W. J. Couch +31 more
TL;DR: In this paper, the mass density, Omega_M, and cosmological-constant energy density of the universe were measured by the analysis of 42 Type Ia supernovae discovered by the Supernova Cosmology Project.
Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant To Appear in the Astronomical Journal
Adam G. Riess,Alexei V. Filippenko,Peter Challis,A. Clocchiatti,Alan H. Diercks,R. L. Gilliland,Craig J. Hogan,Saurabh Jha,Robert P. Kirshner,Bruno Leibundgut,David J Reiss,Brian P. Schmidt,Robert A. Schommer,R. Chris Smith,Jason Spyromilio,Christopher W. Stubbs,Nicholas B. Suntzeff,John L. Tonry +17 more
TL;DR: The spectral and photometric observations of 10 type Ia supernovae (SNe Ia) in the redshift range 0.16 � z � 0.62 were presented in this paper.