Phantom Mimicry on the Normal Branch of a DGP-inspired Braneworld Scenario with Curvature Effect

It has been shown recently that phantom-like effect can be realized on the normal branch of the DGP setup without introduction of any phantom matter neither in the bulk nor on the brane and therefore without violation of the null energy condition. It has been shown also that inclusion of the Gauss-Bonnet term in the bulk action modifies this picture via curvature effects. Here, based on the Lue-Starkman conjecture on the dynamical screening of the brane cosmological constant in the DGP setup, we extend this proposal to a general DGP-inspired $f(R,\phi)$ model that stringy effects in the ultra-violet sector of the theory are taken into account by inclusion of the Gauss-Bonnet term in the bulk action. We study cosmological dynamics of this setup, especially its phantom-like behavior and possible crossing of the phantom divide line especially with a non-minimally coupled quintessence field on the brane. In this setup, scalar field and curvature quintessence are treated in a unified framework.Comment: 25 Figures, To appear in MPL

Holographic Dark Energy from a Modified GBIG Scenario

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 canonical scalar field on the brane. Through a perturbational approach to calculate the effective gravitation constant on the brane, we examine the outcome of this model as a candidate for holographic dark energy.Comment: 13 pages, accepted for publication in IJMP

Braneworld setup and embedding in teleparallel gravity

We construct the setup of a five-dimensional braneworld scenario in teleparallel gravity. Both cases of Minkowski and Friedmann-Robertson-Walker branes embedded in Anti de Sitter bulk are studied and the effective 4-D action were studied. 4-dimensional local Lorentz invariance is found to be recovered in both cases. However, due to different junction conditions, the equations governing the 4-D cosmological evolution differ from general relativistic case. Using the results of Ref. [13], we consider a simple inflationary scenario in this setup. The inflation parameters are found to be modified compared to general relativistic case.Comment: 21 pages, no figure, Title Changed, Accepted for Publication in Phys. Lett.

Bounds on quantum gravity parameter from the SU(2)SU(2) NJL effective model of QCD

Existence of a minimal measurable length, as an effective cutoff in the ultraviolet regime, is a common feature of all approaches to the quantum gravity proposal. It is widely believed that this length scale will be of the order of the Planck length $\lambda=\lambda_0\,l_{_{\rm Pl}}$, where $\lambda_0\sim{\mathcal O}(1)$ is a dimensionless parameter that should be fixed only by the experiments. This issue can be taken into account through the deformed momentum spaces with compact topologies. In this paper, we consider minimum length effects on the physical quantities related to three parameters of the $SU(2)$ Nambu-Jona-Lasinio effective model of QCD by means of the deformed measure which is defined on compact momentum space with ${\mathbf S}^3$ topology. This measure is suggested by the doubly special relativity theories, Snyder deformed spaces, and the deformed algebra that is obtained in the light of the stability theory of Lie algebras. Using the current experimental data of the particle physics collaboration, we constraint quantum gravity parameter $\lambda_0$ and we compare our results with bounds that are arisen from the other experimental setups.Comment: 10 pages, no figure, accepted for publication in Europhysics Letter

Noncommutative Inspired Reissner-Nordstr\"om Black Holes in Large Extra Dimensions

Recently, a new noncommutative geometry inspired solution of the coupled Einstein-Maxwell field equations including black holes in 4-dimension is found. In this paper, we generalize some aspects of this model to the Reissner-Nordstr\"om (RN) like geometries with large extra dimensions. We discuss Hawking radiation process based on noncommutative inspired solutions. In this framework, existence of black hole remnant and possibility of its detection in LHC are investigated.Comment: 24 pages, 12 figures, revised version to appear in Commun. Theor. Phy