Related papers: Modified Gravitational Theory and the Gravity Prob…
The vacuum solutions in brane gravity differ from those in 4D by a number of additional terms and reduce to the familiar Schwarzschild metric at small distances. We study the possible roles that such terms may play in the precession of…
We discuss a modified gravity model which fits cosmological observations at a level statistically indistinguishable from $\Lambda$CDM and at the same time predicts very large deviations from General Relativity (GR) in the propagation of…
Among the effects predicted by the General Theory of Relativity for the orbital motion of a test particle, the post-Newtonian gravitomagnetic Lense-Thirring effect is very interesting and, up to now, there is not yet an undisputable…
Modified gravity theories can produce strong signals in the vicinity of the saddles of the total gravitational potential. In a sub-class of these models this translates into diverging time-delays for echoes crossing the saddles. Such models…
Gravitational waves (GWs) are direct probes of cosmological gravity, sensitive to space-time inhomogeneities along their propagation. The presence of massive objects breaks homogeneity and isotropy, allowing for new interactions between…
General Relativity (GR) was proven via the direct detection of gravitational waves from the mergers of the binary black holes and binary neutron stars by the Advanced LIGO and Advanced Virgo detectors. These detections confirmed the…
Gravitational waves (GW), as light, are gravitationally lensed by intervening matter, deflecting their trajectories, delaying their arrival and occasionally producing multiple images. In theories beyond general relativity (GR), new…
Strong gravitational lensing by galaxies provides us with a unique opportunity to understand the nature of gravity on galactic and extra-galactic scales. In this paper, we propose a new multimessenger approach using data from both…
In this paper, we quantify the ability of a future measurement of the Sandage-Loeb test signal from the Cosmic-Dynamic-Experiment-like spectrograph to constrain some popular modified gravity theories including DGP brane-world scenario,…
In several classes of modified gravity theories, extra degrees of freedom are not completely screened in the interiors of stellar and substellar objects. In such theories, the hydrostatic equilibrium condition inside these objects is…
We study gravito-magnetic effects in the Palatini formalism of f(R) gravity. On using the Kerr-de Sitter metric, which is a solution of f(R) field equations, we calculate the impact of f(R) gravity on the gravito-magnetic precession of an…
A quantum-mechanical theory of gravitation is presented, where the motion of particles is based on the optics of de Broglie waves. Here the large-scale geometry of the universe is inherently flat, and its age is not constrained to < 13 Gyr.…
In this lecture I address the issue of possible large distance modification of gravity and its observational consequences. Although, for the illustrative purposes we focus on a particular simple generally-covariant example, our conclusions…
We analyze the Jordan-Brans-Dicke model (JBD) of gravity, where deviations from General Relativity (GR) are described by a scalar field non-minimally coupled to gravity. The theory is characterized by a constant coupling parameter,…
Joint gravitational-wave (GW) and $\gamma$-ray burst (GRB) observations are among the best prospects for standard siren cosmology. However, the strong selection effect for the coincident GRB detection, which is possible only for sources…
Canonically, `classic' tests of general relativity (GR) include perihelion precession, the bending of light around stars, and gravitational redshift; `modern' tests have to do with, inter alia, relativistic time delay, equivalence principle…
The general theory of relativity is currently the accepted theory of gravity and as such, a large repository of test results has been obtained since its inception in 1915. However, in this paper we only focus on what are considered as the…
We consider models of Extended Gravity and in particular, generic models containing scalar-tensor and higher-order curvature terms, as well as a model derived from noncommutative spectral geometry. Studying, in the weak-field approximation,…
Screened modified gravity theories evade the solar system tests that have proved prohibitive for classical alternative gravity theories. In many cases, they do not fit into the PPN formalism. The environmental dependence of the screening…
We review recent progress in the construction of modified gravity models as alternatives to dark energy as well as the development of cosmological tests of gravity. Einstein's theory of General Relativity (GR) has been tested accurately…