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

AbstractWe consider modified gravity cosmological models that can be transformed into two-field chiral cosmological models by the conformal metric transformation. For the $$R^2$$ R 2 gravity model with an additional scalar field and the corresponding two-field model with the cosmological constant and nonstandard kinetic part of the action, the general solutions have been obtained in the spatially flat FLRW metric. We analyze the correspondence of the cosmic time solutions obtained and different possible evolutions of the Hubble parameters in the Einstein and Jordan frames.

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Cosmological constant Λ in f(R,T) modified gravity

International Journal of Geometric Methods in Modern Physics ◽

10.1142/s0219887816500584 ◽

2016 ◽

Vol 13 (05) ◽

pp. 1650058 ◽

Cited By ~ 19

Author(s):

Gyan Prakash Singh ◽

Binaya Kumar Bishi ◽

Pradyumn Kumar Sahoo

Keyword(s):

Cosmological Model ◽

Cosmological Constant ◽

Modified Gravity ◽

Bianchi Type ◽

Field Equations ◽

Type Iii ◽

Expansion Scalar ◽

Modified Theory Of Gravity ◽

Shear Scalar ◽

Modified Theory

In this paper, we have studied the Bianchi type-III cosmological model in the presence of cosmological constant in the context of [Formula: see text] modified theory of gravity. Here, we have discussed two classes of [Formula: see text] gravity, i.e. [Formula: see text] and [Formula: see text]. In both classes, the modified field equations are solved by the relation expansion scalar [Formula: see text] that is proportional to shear scalar [Formula: see text] which gives [Formula: see text], where [Formula: see text] and [Formula: see text] are metric potentials. Also we have discussed some physical and kinematical properties of the models.

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

10.1145/3463858.3463879 ◽

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

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On a Generalization of the Modified Gravity Model

Springer Proceedings in Mathematics & Statistics - Topics in Statistical Simulation ◽

10.1007/978-1-4939-2104-1_43 ◽

2014 ◽

pp. 439-446

Author(s):

Diana Santalova

Keyword(s):

Gravity Model ◽

Modified Gravity

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Vacuum Energy Fluctuations, The Induced Cosmological Constant and Cosmological Reconstruction in Non-Minimal Modified Gravity Models

The Open Astronomy Journal ◽

10.2174/1874381101003010020 ◽

2010 ◽

Vol 3 (1) ◽

pp. 20-29 ◽

Cited By ~ 1

Author(s):

Guido Cognola ◽

Emilio Elizalde Shin'ichi Nojiri ◽

Sergei D. Odintsov

Keyword(s):

Cosmological Constant ◽

Modified Gravity ◽

Vacuum Energy ◽

Gravity Models ◽

Modified Gravity Models

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Some Cosmological Solutions of a New Nonlocal Gravity Model

Symmetry ◽

10.3390/sym12060917 ◽

2020 ◽

Vol 12 (6) ◽

pp. 917

Author(s):

Ivan Dimitrijevic ◽

Branko Dragovich ◽

Alexey S. Koshelev ◽

Zoran Rakic ◽

Jelena Stankovic

Keyword(s):

General Relativity ◽

Dark Energy ◽

Analytic Function ◽

Cosmological Constant ◽

Explicit Form ◽

Gravity Model ◽

Necessary Conditions ◽

Equations Of Motion ◽

Nonlocal Operator ◽

Cosmological Solutions

In this paper, we investigate a nonlocal modification of general relativity (GR) with action S = 1 16 π G ∫ [ R − 2 Λ + ( R − 4 Λ ) F ( □ ) ( R − 4 Λ ) ] − g d 4 x , where F ( □ ) = ∑ n = 1 + ∞ f n □ n is an analytic function of the d’Alembertian □. We found a few exact cosmological solutions of the corresponding equations of motion. There are two solutions which are valid only if Λ ≠ 0 , k = 0 , and they have no analogs in Einstein’s gravity with cosmological constant Λ . One of these two solutions is a ( t ) = A t e Λ 4 t 2 , that mimics properties similar to an interference between the radiation and the dark energy. Another solution is a nonsingular bounce one a ( t ) = A e Λ t 2 . For these two solutions, some cosmological aspects are discussed. We also found explicit form of the nonlocal operator F ( □ ) , which satisfies obtained necessary conditions.

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