相关论文: Dark energy as a geometrical effect in geodetic br…
We discuss a nonlocal modification of gravity obtained adding a term $m^2 R\,\Box^{-2}R$ to the Einstein-Hilbert action. We find that the mass parameter $m$ only affects the non-radiative sector of the theory, while the graviton remains…
I examine how two specific examples of modified gravity explanations of cosmic acceleration help us understand some general problems confronting cosmological tests of gravity: how do we distinguish modified gravity from dark energy if they…
We consider a five dimensional DGP-brane scenario endowed with a non-minimally coupled scalar field within the context of Brans-Dicke theory. This theory predicts that the mass appearing in the gravitational potential is modified by the…
In this paper we first obtain Friedmann equations for the $(n-1)$-dimensional brane embedded in the $(n+1)$-dimensional bulk, with intrinsic curvature term of the brane included in the action (DGP model). Then, we show that one can always…
A general analysis of the induced brane dynamics is performed when the intrinsic curvature term is included in the action. Such a term is known to cause dramatic changes and is generically induced by quantum corrections coming from the bulk…
We study how the DGP (Dvali-Gabadadze-Porrati) brane affects particle dynamics in linearized approximation. We find that once the particle is removed from the brane it is repelled to the bulk. Assuming that the cutoff for gravitational…
The effective Friedmann equation describing the evolution of the brane Universe in the cosmology of the Randall-Sundrum model includes a dark (or mirage or Weyl) radiation term. The brane evolution can be interpreted as the motion of the…
We construct a holographic dark energy model in a braneworld setup that gravity is induced on the brane embedded in a bulk with Gauss-Bonnet curvature term. We include possible modification of the induced gravity and its coupling with a…
A rare coincidence of scales in standard particle physics is needed to explain why $\Lambda$ or the negative pressure of cosmological dark energy (DE) coincides with the positive pressure $P_0$ of random motion of dark matter (DM) in bright…
In this work, we propose a new model that combines holographic dark energy with modified gravity $f(Q,T)$ to explore a possible explanation for the accelerated expansion of the universe. Since there are several tensions of cosmological…
In this paper we investigate the cosmological effects of modified gravity with string curvature corrections added to Einstein-Hilbert action in the presence of a dynamically evolving scalar field coupled to Riemann invariants. The scenario…
This study aims to investigate the impact of dark energy in cosmological scenarios by exploiting $f(\bar{R},\bar{T})$ gravity within the framework of a {\it non-standard} theory, called {\it {\bf K-}essence} theory, where $\bar{R}$…
We consider multidimensional cosmological model with a higher-dimensional product manifold M = R x R^{d_0} x H^{d_1}/\Gamma where R^{d_0} is d_0-dimensional Ricci-flat external (our) space and H^{d_1}/\Gamma is d_1-dimensional compact…
In this work we investigate the background dynamics when dark energy is coupled to dark matter with a suitable interaction in the universe described by brane cosmology. Here DGP and the RSII brane models have been considered separately.…
There is now strong observational evidence that the expansion of the universe is accelerating. The standard explanation invokes an unknown "dark energy" component. But such scenarios are faced with serious theoretical problems, which has…
Recently we have derived a set of mapping relations that enables the reconstruction of the family of Horndeski scalar-tensor theories which reproduce the background dynamics and linear perturbations of a given set of effective field theory…
Realizing dark energy and the observed de Sitter spacetime in quantum gravity has proven to be obstructed in most every usual approach. We argue that additional degrees of freedom of the left- and right-movers in string theory and a…
In this study, we explore the cosmological implications of a modified gravity theory characterized by the function \( f(R, \Sigma, T) \), where \( R \) is the Ricci scalar, \( \Sigma \) represents a geometric deformation term, and \( T \)…
The late-time cosmic acceleration may be due to infra-red modifications of General Relativity. In particular, we consider a maximal extension of the Hilbert-Einstein action and analyze several interesting features of the theory. Generally,…
We have constructed a dark energy cosmological model in the framework of generalized Brans Dicke theory (GBD) with a self-interacting potential. The source of dark energy is considered through a unified dark fluid (UDF) characterized by a…