We review the topic of 4D Einstein-Gauss-Bonnet gravity, which has been subject considerable interest over past two years. Our begins with a general introduction to Lovelock's theorem, and Gauss-Bonnet terms in action for gravity. These areas are fundamental importance understanding modified theories inform our subsequent discussion recent attempts include effects term four space-time dimension...

Our first goal in this work is to study general and model-independent properties of cyclic cosmologies. The large number studies bouncing cosmologies different scenarios published recently calls for a proper understanding the universal models. We thus review further elaborate common physical geometrical various classes models then discuss how Universe can be treated as dynamic system. two theor...

We discuss class of doubled geometry models with diagonal metrics. Based on the analysis known examples we formulate a hypothesis that supports treating them as modified bimetric gravity theories. Certain steps towards generic case are then performed.

The various options for a quantum theory of gravity are canvassed. Worries about the consistency and physical plausibility of hybrid theories are laid to rest. These hybrid theories—mongrel gravity—comprise the only current, actual theories of gravity, and they also offer legitimate promise for discovering the full theory of gravity. These theories provide an interesting example of scientific r...

Different formulations of modified Newtonian dynamics predict somewhat different rotation curves for the same mass distribution. Here I consider a global attribute of the rotation curve that might provide a convenient discriminant between theories when applied to isolated, pure-disk galaxies that are everywhere deep in the modified Newtonian dynamics regime. This parameter is Q ≡ V(2)/V(∞)(2), ...

We explore the signatures of quintessence and modified gravity theories in the relativistic description of galaxy clustering within a parametrized post-Friedmann framework. For this purpose, we develop a calibration method to consistently account for horizon-scale effects in the linear parametrized post-Friedmann perturbations of minimally and nonminimally coupled scalar-tensor theories and tes...

Abstract Since the discovery of accelerated expansion present universe, significant theoretical developments have been made in area modified gravity. In meantime, cosmological observations providing more high-quality data, allowing us to explore gravity on scales. To bridge recent and observations, we an overview a variety theories observables cosmic microwave background large-scale structure, ...

In general relativity, a gravitational wave propagates with the speed of light, but inthe alternative theories gravity, propagation could deviate from lightdue to modification gravity. Gravitational waves are influenced by modified gravityduring at cosmological distance. this paper, we investigate thepropagation generalized Proca consideringgravitational as field in spacetime perturbing flatspa...

The homotopy analysis method (HAM) is a useful to derive analytical approximate solutions of black holes in modified gravity theories. In this paper, we study the Einstein–Weyl coupled with Maxwell field and obtain approximation for charged by using HAM. It found that are sufficiently accurate entire spacetime outside hole’s event horizon also consistent numerical ones Einstein–Maxwell–Weyl gra...

A bstract We study slowly rotating black hole solutions in the six independent theories of Quartic Generalized Quasi-topological Gravity four dimensions. Unlike static case for which all yield same solution, holes we obtain distinct results five out theories. Working to leading order rotation parameter, find that equations characterizing these can be reduced second each theory, similar what has...