scholarly journals On the Need of a New Geometrical Term—“Conjugate Angles.”

Nature ◽  
1892 ◽  
Vol 47 (1201) ◽  
pp. 8-8
Author(s):  
A. M. WORTHINGTON
Keyword(s):  
Geometrical Term

scholarly journals BRANEWORLDS AND DARK MATTER

2011 ◽  
Vol 20 (01) ◽  
pp. 77-91 ◽  
Author(s):  
SHAHAB SHAHIDI ◽  
HAMID REZA SEPANGI
Keyword(s):  
Dark Matter ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Gauge Fields ◽  
Anisotropic Energy ◽  
The Galaxy ◽  
Virial Mass ◽  
Braneworld Model ◽  
Geometrical Term ◽  
Galaxy Rotation Curves

Two problems related to dark matter are considered in the context of a braneworld model in which the confinement of gauge fields on the brane is achieved by invoking a confining potential. First, we show that the virial mass discrepancy can be addressed if the conserved geometrical term appearing in this model is considered as an energy–momentum tensor of an unknown type of matter, the so-called X-matter whose equation of state (EoS) is also obtained. Second, the galaxy rotation curves are explained by assuming an anisotropic energy–momentum tensor for the X-matter.

scholarly journals Lyra’s cosmology of homogeneous and isotropic universe in Brans–Dicke theory

2020 ◽  
pp. 2150029
Author(s):  
Rajendra Prasad ◽  
Lalit Kumar Gupta ◽  
Anil Kumar Yadav
Keyword(s):  
Cosmological Model ◽  
Deceleration Parameter ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Density Parameter ◽  
Field Equations ◽  
Present Universe ◽  
Age Of The Universe ◽  
Geometrical Term ◽  
The Universe ◽  
Matter Energy

In this paper, we investigate a scalar field Brans–Dicke cosmological model in Lyra’s geometry which is based on the modifications in a geometrical term as well as energy term of Einstein’s field equations. We have examined the validity of the proposed cosmological model on the observational scale by performing statistical analysis from the latest [Formula: see text] and SN Ia observational data. We find that the estimated values of Hubble’s constant and matter energy density parameter is in agreement with their corresponding values, obtained from recent observations of Wilkinson Microwave Anisotropy Probe (WMAP) and Plank collaboration. We also derived the deceleration parameter, age of the universe and jerk parameter in terms of red-shift and computed its present values. The dynamics of the deceleration parameter in the derived model of the universe show a signature flipping from positive to a negative value and also indicate that the present universe is in the accelerating phase.

scholarly journals Traversable wormholes in the traceless f(R,T) gravity

2021 ◽  
pp. 2150100
Author(s):  
Parbati Sahoo ◽  
P. H. R. S. Moraes ◽  
Marcelo M. Lapola ◽  
P. K. Sahoo
Keyword(s):  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Energy Conditions ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Shape Functions ◽  
Anisotropic Matter ◽  
Traversable Wormholes ◽  
Theory Of Gravitation ◽  
Geometrical Term

Wormholes are tunnels connecting different regions in spacetime. They were obtained originally as a solution for Einstein’s General Theory of Relativity and according to this theory they need to be filled by an exotic kind of anisotropic matter. In the present sense, by “exotic matter” we mean matter that does not satisfy the energy conditions. In this paper, we propose the modeling of traversable wormholes (i.e. wormholes that can be safely crossed) within an alternative gravity theory that proposes an extra material (rather than geometrical) term in its gravitational action, namely the traceless [Formula: see text] theory of gravitation, with [Formula: see text] and [Formula: see text] being, respectively, the Ricci scalar and trace of the energy–momentum tensor. Our solutions are obtained from well-known particular cases of the wormhole metric potentials, namely redshift and shape functions. In possession of the solutions for the wormhole material content, we also apply the energy conditions to them. The features of those are carefully discussed.

ON THE GEOMETRICAL TERM RADIUS IN ANCIENT LATIN

Philologus ◽  
2013 ◽  
Vol 157 (1) ◽  
Author(s):  
Erik Bohlin
Keyword(s):  
Geometrical Term

scholarly journals Phantom fluid supporting traversable wormholes in alternative gravity with extra material terms

2018 ◽  
Vol 27 (16) ◽  
pp. 1950004 ◽  
Author(s):  
P. K. Sahoo ◽  
P. H. R. S. Moraes ◽  
Parbati Sahoo ◽  
G. Ribeiro
Keyword(s):  
State Parameter ◽  
Relativity Theory ◽  
Energy Conditions ◽  
Shape Functions ◽  
General Relativity Theory ◽  
Anisotropic Matter ◽  
Traversable Wormholes ◽  
Geometrical Term ◽  
Alternative Gravity Theory ◽  
Alternative Gravity

Wormholes are tunnels connecting different regions in spacetime. They were obtained originally as a solution for Einstein’s General Relativity theory and according to this theory, they need to be filled by an exotic kind of anisotropic matter. In the present sense, by “exotic matter”, we mean matter that does not satisfy the energy conditions. In this paper, we propose the modeling of wormholes within an alternative gravity theory that proposes an extra material (rather than geometrical) term in its gravitational action. Our solutions are obtained from well-known particular cases of the wormhole metric potentials, named redshift and shape functions, and yield the wormholes to be filled by a phantom fluid, that is, a fluid with equation of state parameter [Formula: see text]. In possession of the solutions for the wormhole material content, we also apply the energy conditions to them. The features of those are carefully discussed.

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