Skip to Content

Universe, Volume 1, Issue 3

2015 December - 5 articles

Cover Story: The early inflation, the intermediate decelerating expansion and the late acceleration of the Universe can be described in a unified manner by a quadratic equation of state. The coefficients of this equation of state involve the Planck density ρP (vacuum energy) and the cosmological density ρΛ (dark energy). This equation of state provides a fully analytical solution of the Friedmann equations describing the whole cosmic history of the Universe from a primordial Planck era to a final de Sitter era. This cosmological model avoids the Big Bang singularity and leads to a smooth transition from the inflation era to the radiation era. It also exhibits a nice symmetry between the early and the late Universe. The Planck density ρP and the cosmological density ρΛ represent fundamental upper and lower density bounds differing by 123 orders of magnitude. View

Articles (5)

  • Article
  • Open Access
8 Citations
5,796 Views
30 Pages

1 December 2015

In the chameleon mechanism, a field (typically scalar) has a mass that depends on the matter density of the environment: the larger is the matter density, the larger is the mass of the chameleon. We briefly review some aspects of chameleonic theories...

(This article belongs to the Special Issue Modified Gravity Cosmology: From Inflation to Dark Energy)
  • Article
  • Open Access
11 Citations
6,622 Views
24 Pages

25 November 2015

We consider a parametrized torsion gravity model for Riemann–Cartan geometry around a rotating axisymmetric massive body. In this model, the source of torsion is given by a circulating vector potential following the celestial parallels around the rot...

(This article belongs to the Special Issue 100 Years of Chronogeometrodynamics: the Status of the Einstein's Theory of Gravitation in Its Centennial Year)
  • Article
  • Open Access
11 Citations
5,475 Views
10 Pages

Thermodynamic Analysis of Non-Linear Reissner-Nordström Black Holes

  • Jose A. R. Cembranos,
  • Álvaro De la Cruz-Dombriz and
  • Javier Jarillo

16 November 2015

In the present article we study the Inverse Electrodynamics Model. This model is a gauge and parity invariant non-linear Electrodynamics theory, which respects the conformal invariance of standard Electrodynamics. This modified Electrodynamics model,...

(This article belongs to the Collection Open Questions in Black Hole Physics)
  • Article
  • Open Access
38 Citations
9,048 Views
55 Pages

6 November 2015

We develop a cosmological model based on a quadratic equation of state \(p/c^2=-(\alpha+1){\rho^2}/{\rho_P}+\alpha\rho-(\alpha+1)\rho_ {\Lambda}\), where \(\rho_P\) is the Planck density and \(\rho_{\Lambda}\) the cosmological density, ``unifying'' v...

(This article belongs to the Special Issue Modified Gravity Cosmology: From Inflation to Dark Energy)
  • Article
  • Open Access
11 Citations
7,799 Views
50 Pages

Expanding Space, Quasars and St. Augustine’s Fireworks

  • Olga I. Chashchina and
  • Zurab K. Silagadze

1 October 2015

An attempt is made to explain time non-dilation allegedly observed in quasar light curves. The explanation is based on the assumption that quasar black holes are, in some sense, foreign for our Friedmann-Robertson-Walker universe and do not participa...

XFacebookLinkedIn
Universe - ISSN 2218-1997