Results 51 to 60 of about 540,486 (189)
Classical and Quantum GravityAbstract A complete canonical formulation of general covariance makes it possible to construct new modified theories of gravity that are not of higher-curvature form, as shown here in a spherically symmetric setting. The usual uniqueness theorems are evaded by using a crucial and novel ingredient, allowing for fundamental fields of ...
Martin Bojowald, Erick I Duque
openaire +2 more sources
Born–Infeld-type modified gravity [PDF]
International Journal of Geometric Methods in Modern Physics, 2019 We propose and investigate the modified Born–Infeld-type gravity model with the function [Formula: see text]. At different values of the dimensionless parameter [Formula: see text], the action is converted into some models including general relativity ([Formula: see text]), the Starobinsky model ([Formula: see text]), the exponential model of gravity (
openaire +2 more sources
The instabilities and (anti)-evaporation of Schwarzschild-de Sitter black holes in modified gravity
, 2013 We investigate the future evolution of Nariai black hole which is extremal limit of Schwarzschild-de Sitter one in modified gravity. The perturbations equations around Nariai black hole are derived in static and cosmological patches for general $F(R ...
Momeni, D. +3 more
core +1 more source
Charged gravastars in modified gravity [PDF]
Physical Review D, 2019 23 pages, 6 figures, final version to appear in Physical Review ...
Yousaf, Z. +3 more
openaire +2 more sources
Stability in generalized Modified Gravity [PDF]
AIP Conference Proceedings, 2009 The stability issue of a large class of modified gravitational models is discussed with particular emphasis to de Sitter solutions. Three approaches are briefly presented and the generalization to more general cases is mentioned.
S. Zerbini, Shaaban Khalil
openaire +5 more sources
Born–Infeld-Like Modified Gravity [PDF]
International Journal of Theoretical Physics, 2013 RevTex, 5 pages, one figure, minor corrections, references added, journal version, accepted in ...
openaire +3 more sources
Dark Energy versus Modified Gravity [PDF]
Physical Review Letters, 2007 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 led to increased interest in models where instead General Relativity is modified in a way that leads to the observed
Kunz, Martin, Sapone, Domenico
openaire +4 more sources
Modified gravity one-loop partition function
European Physical Journal C: Particles and Fields, 2018 The one-loop partition function of the $$f(R,R_{\mu \nu }R^{\mu \nu })$$ f(R,RμνRμν) gravity theory is obtained around $$\hbox {AdS}_4$$ AdS4 background.
Shahab Shahidi +3 more
doaj +1 more source
Relic gravitational wave spectrum, the trans-Planckian physics and Ho\v{r}ava-Lifshitz gravity
, 2009 We calculate the spectrum of the relic gravitational wave due to the trans-Planckian effect in which the standard linear dispersion relations may be modified. Of the modified dispersion relations suggested in literatures which have investigated the trans-
Koh, Seoktae
core +1 more source
, 2018 We present a new parameterization for the equation of state (EoS) $ _X=P_X/ _X$, which can reproduce a $f(R)$-like evolution with a precision between $[0.5\%-0.8\%]$ over the numerical solutions. Also, our proposal can render a variety of popular $f(R)$ models that are considered as viable candidates for the cosmic late time acceleration.
Jaime, Luisa G. +2 more
openaire +2 more sources