scholarly journals Constraints on f(R) and normal-branch Dvali-Gabadadze-Porrati modified gravity model parameters with cluster abundances and galaxy clustering

2021 ◽  
Vol 104 (10) ◽  
Author(s):  
Rayne Liu ◽  
Georgios Valogiannis ◽  
Nicholas Battaglia ◽  
Rachel Bean
Keyword(s):  
Gravity Model ◽  
Modified Gravity ◽  
Model Parameters ◽  
Galaxy Clustering ◽  
Normal Branch

scholarly journals Cosmology with the Einstein Telescope: No Slip Gravity model and redshift specifications

2021 ◽  
Author(s):  
Ayan Mitra ◽  
Jurgen Mifsud ◽  
David F Mota ◽  
David Parkinson
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Gravity Model ◽  
Modified Gravity ◽  
Cosmological Parameters ◽  
Gravitational Theory ◽  
Model Parameters ◽  
Einstein Telescope ◽  
Interferometric Detectors ◽  
Parameter Constraints

Abstract The Einstein Telescope and other third generation interferometric detectors of gravitational waves are projected to be operational post 2030. The cosmological signatures of gravitational waves would undoubtedly shed light on any departure from the current gravitational framework. We here confront a specific modified gravity model, the No Slip Gravity model, with forecast observations of gravitational waves. We compare the predicted constraints on the dark energy equation of state parameters $w_0^{}-w_a^{}$, between the modified gravity model and that of Einstein gravity. We show that the No Slip Gravity model mimics closely the constraints from the standard gravitational theory, and that the cosmological constraints are very similar. The use of spectroscopic redshifts, especially in the low–redshift regime, lead to significant improvements in the inferred parameter constraints. We test how well such a prospective gravitational wave dataset would function at testing such models, and find that there are significant degeneracies between the modified gravity model parameters, and the cosmological parameters that determine the distance, due to the gravitational wave dimming effect of the modified theory.

BOUNDS ON f(G) GRAVITY FROM ENERGY CONDITIONS

2010 ◽  
Vol 25 (27) ◽  
pp. 2325-2332 ◽  
Author(s):  
PUXUN WU ◽  
HONGWEI YU
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Energy Density ◽  
Modified Gravity ◽  
Energy Conditions ◽  
Model Parameters ◽  
Effective Energy ◽  
Raychaudhuri Equation ◽  
Accelerating Expansion

The f(G) gravity is a theory to modify the general relativity and it can explain the present cosmic accelerating expansion without the need of dark energy. In this paper the f(G) gravity is tested with the energy conditions. Using the Raychaudhuri equation along with the requirement that the gravity is attractive in the FRW background, we obtain the bounds on f(G) from the SEC and NEC. These bounds can also be found directly from the SEC and NEC within the general relativity context by the transformations: ρ → ρm + ρE and p → pm + pE, where ρE and pE are the effective energy density and pressure in the modified gravity. With these transformations, the constraints on f(G) from the WEC and DEC are obtained. Finally, we examine two concrete examples with WEC and obtain the allowed region of model parameters.

Multi Depot Vehicle Routing Using Ant Colony Optimization - Trip Assignment of Freight Flow Using Modified Gravity Model

2021 ◽  
Author(s):  
Husnain Saeed ◽  
Shahid Ikramullah ◽  
Mushtaq Khan ◽  
Fahd Amjad ◽  
Liaqat Ali ◽  
...  
Keyword(s):  
Ant Colony Optimization ◽  
Vehicle Routing ◽  
Gravity Model ◽  
Modified Gravity ◽  
Ant Colony ◽  
Freight Flow

scholarly journals Cosmological scaling solutions with tachyon: Modified gravity model

2008 ◽  
Vol 668 (3) ◽  
pp. 182-186 ◽  
Author(s):  
A.A. Sen ◽  
N. Chandrachani Devi
Keyword(s):  
Gravity Model ◽  
Modified Gravity

scholarly journals A new source for a brane cosmological constant from a modified gravity model in the bulk

2009 ◽  
Vol 807 (1-2) ◽  
pp. 56-72 ◽  
Author(s):  
Orfeu Bertolami ◽  
Carla Carvalho ◽  
João N. Laia
Keyword(s):  
Cosmological Constant ◽  
Gravity Model ◽  
Modified Gravity

scholarly journals Dynamics of an Anisotropic Universe inf(R,T)Theory

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
B. Mishra ◽  
Sankarsan Tarai ◽  
S. K. Tripathy
Keyword(s):  
Power Law ◽  
Modified Gravity ◽  
Bianchi Type ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Model Parameters ◽  
Anisotropic Universe ◽  
Expansion Of The Universe ◽  
Physical Features ◽  
The Universe

Dynamics of an anisotropic universe is studied inf(R,T)gravity using a rescaled functionalf(R,T), whereRis the Ricci Scalar andTis the trace of energy-momentum tensor. Three models have been constructed assuming a power law expansion of the universe. Physical features of the models are discussed. The model parameters are constrained from a dimensional analysis. It is found from the work that the anisotropic Bianchi typeVIh(BVIh) model in the modified gravity generally favours a quintessence phase when the parameterhis either-1or0. We may not get viable models in conformity with the present day observation forh=1.

scholarly journals Gravitational collapse of compact stars in f(R) = ξR4 gravity

2021 ◽  
Author(s):  
Jay Solanki
Keyword(s):  
Gravity Model ◽  
Gravitational Collapse ◽  
Analytical Solutions ◽  
Modified Gravity ◽  
Compact Stars ◽  
Physical Parameters ◽  
Field Equations ◽  
Paper Model ◽  
Acceptable Model ◽  
Physical Quantities

In this paper, model of gravitational collapse of anisotropic compact stars in a new theory of [Formula: see text] gravity has been developed. The author considers the modified gravity model of [Formula: see text] to investigate a physically acceptable model of gravitational collapse of anisotropic compact stars. First, the author presents a brief review of the development of field equations of gravitational collapse in [Formula: see text] gravity for a particular interior metric for compact stars. Then analytical solutions for various physical quantities of collapsing anisotropic compact stars in [Formula: see text] gravity have been developed. By analyzing plots of various physical parameters and conditions, it is shown that the model is physically acceptable for describing the gravitational collapse of anisotropic compact stars in [Formula: see text] gravity.

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