Gravitational collapse of interacting combination of dark matter and dark energy in the context of brane world regime

2018 ◽  
Vol 33 (23) ◽  
pp. 1850132 ◽  
Author(s):  
Hasrat Hussain Shah ◽  
Farook Rahaman
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Gravitational Collapse ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Brane World ◽  
Anisotropic Pressure ◽  
Isotropic Pressure ◽  
Polytropic Equation ◽  
De Formula

In the scenario of an optimal consideration that is, homogeneous and flat spacetime, we study the Black Hole (BH) formation from the gravitational collapse of a spherical symmetric clump of matter in the case of the specific Dark Matter (DM) model interacting with Dark Energy (DE) in the context of the brane world regime. This clump of matter constituted of DM, [Formula: see text] and DE, [Formula: see text]. In the present model, we consider anisotropic pressure in the energy–momentum tensor with a polytropic equation of state (EoS), [Formula: see text] and [Formula: see text], [Formula: see text]. Our results show that the gravitational collapse of an interacting combination of DM and DE leads to the formation of BH in the presence of brane tension. Recent work provides the generalization of isotropic pressure to an-isotropic pressure in the energy–momentum tensor for the specific interacting combination model of DM and DE in a brane world regime.

Gravitational collapse of dark matter interacting with dark energy: Black hole formation

2017 ◽  
Vol 26 (13) ◽  
pp. 1750142 ◽  
Author(s):  
Hasrat Hussain Shah ◽  
Quaid Iqbal
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Dark Energy ◽  
Gravitational Collapse ◽  
Anisotropic Pressure ◽  
Spherically Symmetric ◽  
Hole Formation ◽  
White Hole ◽  
De Formula ◽  
Symmetric Star

In this work, we study the gravitational collapsing process of a spherically symmetric star constitute of Dark Matter (DM), [Formula: see text], and Dark Energy (DE) [Formula: see text]. In this model, we use anisotropic pressure with Equation of State (EoS) [Formula: see text] and [Formula: see text], [Formula: see text]. It reveals that gravitational collapse of DM and DE with interaction leads to the formation of the black hole. When [Formula: see text] (phantoms), dust and phantoms could be ejected from the death of white hole. This emitted matter again undergoes to collapsing process and becomes the black hole. This study gives the generalization for isotropy of pressure in the fluid to anisotropy when there will be interaction between DM and DE.

Black hole formation due to collapsing dark matter in a presence of dark energy in the brane-world scenario

2018 ◽  
Vol 27 (03) ◽  
pp. 1850020 ◽  
Author(s):  
Hasrat Hussain Shah
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Gravitational Collapse ◽  
Naked Singularity ◽  
Brane World ◽  
Spherically Symmetric ◽  
Hole Formation ◽  
De Formula ◽  
Symmetric Star ◽  
Collapse Process

In the last three to four decades, various programs have been studied in order to investigate the final fate of gravitational collapse of massive astronomical objects. In the theoretical context, Black Holes (BHs) are the consequence of final stage of the gravitational collapse. In this work, we investigated the gravitational collapse process of a spherically symmetric star constituted of dark matter (DM), [Formula: see text], and Dark Energy (DE), [Formula: see text] in the context of the brane-world scenario. In our model, we discussed the anisotropy of the pressure in a fluid with Equation of State (EoS) [Formula: see text] and [Formula: see text], [Formula: see text]. We briefly discussed various cases of gravitational collapse and it is found that BH can be formed by the gravitational collapse in brane-world regime while in some cases there is only a naked singularity at their end state.

The curvature effect on the gravitational collapse of interacting and non-interacting combination of dark matter and dark energy

2020 ◽  
Vol 35 (17) ◽  
pp. 2050078
Author(s):  
S. Z. Abbas ◽  
H. H. Shah ◽  
W. Chammam ◽  
H. Sun ◽  
Wasim Ul Haq ◽  
...  
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Gravitational Collapse ◽  
Space Time ◽  
Relativistic Astrophysics ◽  
Spherically Symmetric ◽  
Curvature Effect ◽  
De Formula ◽  
General Relativistic

The study of gravitational collapse is a very interesting phenomena in general relativistic astrophysics. Here, in this study we investigated the gravitational collapse of a spherically symmetric core of a star, constituted of dark matter (DM) ([Formula: see text]), in dark energy (DE) ([Formula: see text]) background. It was investigated that gravitational collapse of interacting and noninteracting combination of DM and DE yields BH formation. In this work, our main aim is to examine the effect of space–time curvature [Formula: see text] on the gravitational collapse of interacting and noninteracting combination of dark matter and DE. We achieve the visible influence of curvature on gravitational collapse analytically and interpret the results graphically.

scholarly journals Macroscopic Theory of Dark Sector

2014 ◽  
Vol 2014 ◽  
pp. 1-23 ◽  
Author(s):  
Boris E. Meierovich
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Vector Field ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Accelerated Expansion ◽  
Kinetic Term ◽  
Dark Sector ◽  
Macroscopic Theory ◽  
Oscillating Solutions

A simple Lagrangian with squared covariant divergence of a vector field as a kinetic term turned out to be an adequate tool for macroscopic description of the dark sector. The zero-mass field acts as the dark energy. Its energy-momentum tensor is a simple additive to the cosmological constant. Massive fields describe two different forms of dark matter. The space-like massive vector field is attractive. It is responsible for the observed plateau in galaxy rotation curves. The time-like massive field displays repulsive elasticity. In balance with dark energy and ordinary matter it provides a four-parametric diversity of regular solutions of the Einstein equations describing different possible cosmological and oscillating nonsingular scenarios of evolution of the Universe. In particular, the singular big bang turns into a regular inflation-like transition from contraction to expansion with the accelerated expansion at late times. The fine-tuned Friedman-Robertson-Walker singular solution is a particular limiting case at the lower boundary of existence of regular oscillating solutions in the absence of vector fields. The simplicity of the general covariant expression for the energy-momentum tensor allows displaying the main properties of the dark sector analytically. Although the physical nature of dark sector is still unknown, the macroscopic theory can help analyze the role of dark matter in astrophysical phenomena without resorting to artificial model assumptions.

scholarly journals RECONSTRUCTING f(R, T) GRAVITY FROM HOLOGRAPHIC DARK ENERGY

2012 ◽  
Vol 21 (03) ◽  
pp. 1250024 ◽  
Author(s):  
M. J. S. HOUNDJO ◽  
OLIVER F. PIATTELLA
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Dark Energy ◽  
Energy Momentum Tensor ◽  
Holographic Dark Energy ◽  
Momentum Tensor ◽  
Ricci Scalar ◽  
Relativity Theory ◽  
General Relativity Theory ◽  
Theories Of Gravity

We consider cosmological scenarios based on f(R, T) theories of gravity (R is the Ricci scalar and T is the trace of the energy–momentum tensor) and numerically reconstruct the function f(R, T) which is able to reproduce the same expansion history generated, in the standard General Relativity theory, by dark matter and holographic dark energy. We consider two special f(R, T) models: in the first instance, we investigate the modification R + 2f(T), i.e. the usual Einstein–Hilbert term plus a f(T) correction. In the second instance, we consider a f(R) + λT theory, i.e. a T correction to the renown f(R) theory of gravity.

scholarly journals SPHERICALLY SYMMETRIC GRAVITATIONAL COLLAPSE

2009 ◽  
Vol 24 (19) ◽  
pp. 1533-1542 ◽  
Author(s):  
M. SHARIF ◽  
KHADIJA IQBAL
Keyword(s):  
Surface Energy ◽  
Gravitational Collapse ◽  
Curvature Tensor ◽  
Energy Momentum Tensor ◽  
Extrinsic Curvature ◽  
Momentum Tensor ◽  
Spherically Symmetric ◽  
Tangential Pressure ◽  
Symmetric Spacetimes ◽  
Spherically Symmetric Spacetimes

In this paper, we discuss gravitational collapse of spherically symmetric spacetimes. We derive a general formalism by taking two arbitrary spherically symmetric spacetimes with g00 = 1. Israel's junction conditions are used to develop this formalism. The formulas for extrinsic curvature tensor are obtained. The general form of the surface energy–momentum tensor depending on extrinsic curvature tensor components is derived. This leads us to the surface energy density and the tangential pressure. The formalism is applied to two known spherically symmetric spacetimes. The results obtained show the regions for the collapse and expansion of the shell.

Various dark energy models for variables G and Λ in f(R, T) modified theory

2019 ◽  
Vol 34 (13) ◽  
pp. 1950098 ◽  
Author(s):  
Can Aktaş
Keyword(s):  
Dark Energy ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Tachyon Field ◽  
Field Equations ◽  
Frw Universe ◽  
Linearly Varying Deceleration Parameter ◽  
Energy Models ◽  
Modified Theory ◽  
Friedmann Robertson Walker

In this paper, we have researched tachyon field, k-essence and quintessence dark energy (DE) models for Friedmann–Robertson–Walker (FRW) universe with varying G and [Formula: see text] in f(R, T) gravitation theory. The theory of f(R, T) is proposed by Harko et al. [Phys. Rev. D 84, 024020, 2011]. In this theory, R is the Ricci scalar and T is the trace of energy–momentum tensor. For the solutions of field equations, we have used linearly varying deceleration parameter (LVDP), the equation of state (EoS) and the ratio between [Formula: see text] and Hubble parameter. Also, we have discussed some physical behavior of the models with various graphics.

scholarly journals Revised theory of tachyons in general relativity

2017 ◽  
Vol 32 (24) ◽  
pp. 1750126 ◽  
Author(s):  
Charles Schwartz
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Energy Momentum Tensor ◽  
Good Reason ◽  
Momentum Tensor ◽  
Minus Sign

A minus sign is inserted, for good reason, into the formula for the energy–momentum tensor for tachyons. This leads to remarkable theoretical consequences and a plausible explanation for the phenomenon called dark energy in the cosmos.

scholarly journals Field Equations in C4 Space-Time

2018 ◽  
Author(s):  
Dimitris Mastoridis ◽  
K. Kalogirou
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Complex Space ◽  
Energy Momentum Tensor ◽  
Real Space ◽  
Momentum Tensor ◽  
Space Time ◽  
Field Equations ◽  
Geometric Information

We explore the field equations in a 4-d complex space-time, in the same way, that general relativity does for our usual 4-d real space-time, forming this way, a new "general  relativity" in C4 space-time, free of sources. Afterwards, by embedding our usual 4-d real space-time in C4 space-time, we describe  geometrically the energy-momentum tensor Tμν as the lost geometric information of this embedding. We further give possible explanation of dark eld and dark energy.

scholarly journals MODEL MATERI GELAP DUA FLUIDA STATIS DENGAN TAMBAHAN KONSTANTA KOSMOLOGI

2018 ◽  
Vol 3 (2) ◽  
pp. 127-132
Author(s):  
Izrul Supriyadi ◽  
Widya Sawitar ◽  
Esmar Budi ◽  
Riser Fahdiran
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cosmological Constant ◽  
Tangential Velocity ◽  
Momentum Tensor ◽  
Geodesic Equation ◽  
Fluid Models ◽  
Characteristic Energy ◽  
Expansion Model ◽  
Two Fluid

Abstrak Pada persamaan medan gravitasi Einstein terdapat konstanta kosmologi sebagai konstanta alam yang menjelaskan model mengembangnya alam semesta dan yang paling dominan terdapat di jagad raya ini adalah dalam bentuk energi gelap (dark energy). Kami meninjau model objek dua fluida tidak terkopel, seperti layaknya materi gelap (dark matter) atau bintang yang memiliki karakteristik tensor energi-momentum dan kecepatan-4 nya yang berbeda serta bersifat anisotropik, kemudian disatukan sebagai model dua fluida untuk ditinjau persamaan TOV (Tolman-Oppenheimer-Volkoff) dan persamaan geodesiknya dalam menunjukkan sifat gerak dan model dua fluida tersebut. Hasil perhitungan menunjukkan bahwa model ini dapat menjelaskan persamaan potensial efektif dengan tambahan konstanta kosmologi sebagai karakteristik gerak dan kecepatan tangensial partikel uji dalam orbit lingkaran stabil. Kata-kata kunci: konstanta kosmologi, anisotropik, potensial efektif, kecepatan tangensial. Abstract In Einstein's gravitational field equation has been found the cosmological constant as the natural constant that describes the universe's expansion model and the most dominant in the universe is the dark energy form. We review the two objects of fluid models are not coupled, like dark matter or stars which has the different characteristic energy-momentum tensor and four velocities and anisotropic tend, then combined as two-fluid models for TOV (Tolman-Oppenheimer-Volkoff) equation and the geodesic equation to characterize the movement and the two fluid models. The calculation result shows that this model can explain the potential equation with an addition of an effective cosmological constant as the movement characteristic and tangential velocity of a tested particle in a stable circular orbit. Keywords: cosmological constant, anisotropic, effective potential, tangential velocity.

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