showing 9 related works from this author
Cosmological Applications of Extended Electromagnetism
2013
Extended electromagnetism (EE) has been applied to cosmology in various papers. In all of them, the zero order energy density of the EE vector field plays the same role as vacuum energy. Perturbations of this field have been studied by using different approaches. Firstly, some basic equations and ideas are summarized and, then, the CMBFAST code is used to calculate the cosmic microwave background angular power spectrum for appropriate values of the EE parameters. Comparisons of the resulting spectra with a good observational one compatible with WMAP7 (Wilkinson map anisotropy probe 7 years data) seem to be promising. We are currently looking for a set of parameters leading to the best fitti…
Cosmic primordial density fluctuations and Bell inequalities
2023
The temperature measurements, $T$, of the perturbed cosmic microwave background, performed by the cosmic background explorer satellite (COBE), are considered. A dichotomist function, $f = \pm 1$, is defined such that $f =+1$ if $\delta T > 0$ and $f =-1$ if $\delta T < 0$, where $\delta T$ stands for the fluctuation of $T$. Then, it is assumed that behind the appearance of these fluctuations there is local realism. Under this assumption, some specific Clauser-Horne-Shimony-Holt (CHSH) inequalities are proved for these fluctuation temperatures measured by COBE in the different sky directions. The calculation of these inequalities from the actual temperature measurements shows that these ineq…
Testing vector-tensor gravity with current cosmological observations
2015
A certain vector-tensor theory of gravitation (VT) has been recently applied to cosmology (Phys. Rev. D, 89, 2014, 044035). It leads to encouraging results. The zero order energy density of the vector field accounts for the cosmological constant. It has been recently proved that the VT vector field cannot play the role of the electromagnetic field. The evolution of the scalar perturbations is different in VT and general relativity. Tensor fluctuations evolve in the same way in both theories. Here, the VT evolution equations of the scalar modes are appropriately written, and the initial conditions at high redshift - for numerical integration- are given. The codes COSMOMC and CAMB are modifie…
More about a successful vector-tensor theory of gravitation
2016
The vector-tensor (VT) theory of gravitation revisited in this article was studied in previous papers, where it was proved that VT works and deserves attention. New observational data and numerical codes have motivated further development which is presented here. New research has been planed with the essential aim of proving that current cosmological observations, including Planck data, baryon acoustic oscillations (BAO), and so on, may be explained with VT, a theory which accounts for a kind of dark energy which has the same equation of state as vacuum. New versions of the codes CAMB and COSMOMC have been designed for applications to VT, and the resulting versions have been used to get the…
Spherical symmetric dust collapse in a Vector-Tensor gravity
2018
There is a viable vector-tensor gravity (VTG) theory, whose vector field produces repulsive forces leading to important effects. In the background universe, the effect of these forces is an accelerated expansion identical to that produced by vacuum energy (cosmological constant). Here, we prove that another of these effects arises for great enough collapsing masses which lead to Schwarzschild black holes and singularities in general relativity (GR). For these masses, pressure becomes negligible against gravitational attraction and the complete collapse cannot be stopped in the context of GR; however, in VTG, a strong gravitational repulsion could stop the falling of the shells towards the s…
Cosmological perturbations in extended electromagnetism. General gauge invariant approach
2013
A certain vector-tensor (VT) theory is revisited. It was proposed and analyzed as a theory of electromagnetism without the standard gauge invariance. Our attention is first focused on a detailed variational formulation of the theory, which leads to both a modified Lorentz force and the true energy momentum tensor of the vector field. The theory is then applied to cosmology. A complete gauge invariant treatment of the scalar perturbations is presented. For appropriate gauge invariant variables describing the scalar modes of the vector field (A-modes), it is proved that the evolution equations of these modes do not involve the scalar modes appearing in General Relativity (GR-modes), which are…
Interpreting deviations between AR-VTG and GR
2019
The cosmic microwave background (CMB) anisotropies predicted by two cosmological models are compared, one of them is the standard model of general relativity with cold dark matter and cosmological constant, whereas the second model is based on a consistent vector-tensor theory of gravitation explaining solar system and cosmological observations. It is proved that the resulting differences — between the anisotropies of both models — are due to the so-called late integrated Sachs–Wolfe effect and, consequently, cross-correlations between maps of CMB temperatures and tracers of the dark matter distribution could be used in future to select one of the above models. The role of reionization is …
On the viability of a certain vector-tensor theory of gravitation
2010
A certain vector-tensor theory is revisited. Our attention is focused on cosmology. Against previous suggestions based on preliminary studies, it is shown that, if the energy density of the vector field is large enough to play the role of the dark energy and its fluctuations are negligible, the theory is not simultaneously compatible with current observations on: supernovae, the cosmic microwave background (CMB) anisotropy, and the power spectrum of the energy density fluctuations. However, for small enough energy densities of the vector field, the theory becomes compatible with all the above observations and, moreover, it leads to an interesting evolution of the so-called vector cosmologic…
Cosmology in a certain vector-tensor theory of gravitation
2014
We study relevant cosmological topics in the framework of a certain vector-tensor theory of gravitation (hereafter VT). This theory is first compared with the so-called extended electromagnetism (EE). These theories have a notable resemblance and both explain the existence of a cosmological constant. It is shown that, in EE, a positive dark energy density requires a Lagrangian leading to quantum ghosts, whereas VT is free from these ghosts. On account of this fact, the remainder of the paper is devoted to study cosmology in the framework of VT. Initial conditions, at high redshift, are used to solve the evolution equations of all the VT scalar modes. In particular, a certain scalar mode cha…