Related papers: Dark Matter in logarithmic $F(R)$ gravity
In this paper we consider $\phi^2$ scalar field potential as a candidate to dark matter. If it is an ultralight boson particle, it condensates like a Bose-Einstein system at very early times and forms the basic structure of the Universe.…
It is shown that so-called dark energy could possible be a manifestation of the gravitational vortex producing the "gravitomagnetic" (GM) force field: associated with cosmic matter rotation and inertial spacetime frame dragging. The general…
It is a well-known truism, inspired on the general theory of relativity, that gravity gravitates. Here we suggest the possibility that dark matter may be caused by the gravitation of the metric. At first sight this seems impossible since…
It is not easy to treat the spacetime with horizon(s) in the standard mimetic gravity. The solution to this problem has been presented in Phys.~Lett.~B 830 (2022), 137140, where it was suggested to modify the Lagrange multiplier constraint.…
Using Mukhanov-Chamseddine mimetic approach, we study $F(R)$ gravity with scalar potential and Lagrange multiplier constraint. As we demonstrate, for a given $F(R)$ gravity and for suitably chosen mimetic potential, it is possible to…
Flat or almost flat rotation curves of spiral galaxies can be explained by logarithmic gravitational potentials. The field equations of GR admit of spacetime metrics with such behaviors. The scenario can be interpreted either as an…
We consider the cosmologies that arise in a subclass of f(R) gravity with f(R)=R+\mu ^{2n+2}/(-R)^{n} and -1<n<0 in the metric (as opposed to the Palatini) variational approach to deriving the gravitational field equations. The calculations…
The recently suggested generalized unimodular gravity theory, which was originally put forward as a model of dark energy, can serve as a model of cosmological inflation driven by the effective perfect fluid -- the dark purely gravitational…
We describe a novel procedure to map the field equations of nonlinear Ricci-based metric-affine theories of gravity, coupled to scalar matter described by a given Lagrangian, into the field equations of General Relativity coupled to a…
Observations provide increasingly strong evidence that the universe is accelerating. This revolutionary advance in cosmological observations confronts theoretical cosmology with a tremendous challenge, which it has so far failed to meet.…
The violation of the general covariance is proposed as a resource of the gravitational dark matter. The minimal violation of the covariance to the unimodular one is associated with the massive scalar graviton as the simplest representative…
We present a scenario of vector dark matter production during inflation containing a complex inflaton field which is charged under a dark gauge field and which has a symmetry breaking potential. As the inflaton field rolls towards the…
Using modified gravity with non-linear terms of curvature, $R^2$ and $R^{(r +2)}$ (with $r$ being the positive real number and $R$ being the scalar curvature), cosmological scenario,beginning at the Planck scale, is obtained. Here, a…
Modified theories of gravity have been invoked recently as an alternative to dark energy, in an attempt to explain the apparent accelerated expansion of the universe at the present time. In order to describe inhomogeneities in cosmological…
I address some problems encountered in the formulation of relativistic models encompassing the MOND phenomenology of radial acceleration. I explore scalar and vector theories with fractional kinetic terms and $f(R)$-type gravity, demanding…
f(R)-theories of gravity are reviewed in the framework of the matter-antimatter asymmetry in the Universe. The asymmetry is generated by the gravitational coupling of heavy (Majorana) neutrinos with the Ricci scalar curvature. In order that…
To explain the cosmic speed up, brought to light by the recent SNIa and CMB observations, we propose the following: a) In a spacetime endowed with a FRW metric, we choose an empirical scale factor that best explains the observations. b) We…
In this article, we propose different background models of extended theories of gravity, which are minimally coupled to the SM fields, to explain the possibility of genesis of dark matter without affecting the SM particle sector. We modify…
$f(R)$ modifications of Einstein's gravity is an interesting possibility to explain the late time acceleration of the Universe. In this work we explore the cosmological viability of one such $f(R)$ modification proposed in (Kruglov:2013).…
Modified Gauss-Bonnet, i.e, $f(G)$ gravity is a possible explanation of dark energy. Late time cosmology for the $f(G)$ gravity non-minimally coupled with a free massless scalar field have been investigated in Ref. [32]. In this paper we…