A dark matter compact star in the framework of the pseudo-complex general relativity

2017 ◽  
Vol 338 (9-10) ◽  
pp. 1079-1084 ◽  
Author(s):  
D. Hadjimichef ◽  
M.V.T. Machado ◽  
F. Köpp ◽  
G.L. Volkmer ◽  
M. Razeira ◽  
...  
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Compact Star ◽  
Complex General Relativity

Dark Matter Compact Stars in Pseudo-Complex General Relativity

2018 ◽  
pp. 149-167
Author(s):  
D. Hadjimichef ◽  
G. L. Volkmer ◽  
R. O. Gomes ◽  
C. A. Zen Vasconcellos
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Compact Stars ◽  
Complex General Relativity

scholarly journals Mimetic Dark Matter in Pseudo-Complex General Relativity

2017 ◽  
Vol 45 ◽  
pp. 1760012 ◽  
Author(s):  
Guilherme Lorenzatto Volkmer ◽  
Dimiter Hadjimichef
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Degree Of Freedom ◽  
Complex General Relativity

We investigate the dark matter problem in the context of Pseudo-complex General Relativity. A form of gravitational dark matter has recently been studied, the mimetic dark matter, which is a scalar tensor extension for gravity where the conformal degree of freedom is isolated in a covariant way. For such, we perform a combination of both approaches to reveal non trivial results even in the absence of matter. Solutions for different scenarios and possible interpretations are presented.

scholarly journals Ray-tracing in pseudo-complex General Relativity

2014 ◽  
Vol 442 (1) ◽  
pp. 121-130 ◽  
Author(s):  
T. Schönenbach ◽  
G. Caspar ◽  
P. O. Hess ◽  
T. Boller ◽  
A. Müller ◽  
...  
Keyword(s):  
General Relativity ◽  
Ray Tracing ◽  
Complex General Relativity

scholarly journals Neutron stars as probes of dark matter

2020 ◽  
Vol 29 (14) ◽  
pp. 2043028
Author(s):  
M. Ángeles Pérez-García ◽  
Joseph Silk
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Equation Of State ◽  
Neutron Stars ◽  
Internal Structure ◽  
Stellar Objects ◽  
Ordinary Matter ◽  
Stable Solutions ◽  
The Universe

Neutron Stars (NSs) are compact stellar objects that are stable solutions in General Relativity. Their internal structure is usually described using an equation of state that involves the presence of ordinary matter and its interactions. However there is now a large consensus that an elusive sector of matter in the universe, described as dark matter, remains as yet undiscovered. In such a case, NSs should contain both, baryonic and dark matter. We argue that depending on the nature of the dark matter and in certain circumstances, the two matter components would form a mixture inside NSs that could trigger further changes, some of them observable. The very existence of NSs constrains the nature and interactions of dark matter in the universe.

scholarly journals Dark matter from non-relativistic embedding gravity

2021 ◽  
pp. 2150101
Author(s):  
S. A. Paston
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Explicit Form ◽  
Equations Of Motion ◽  
Additional Contribution ◽  
Relativistic Limit ◽  
The Core ◽  
The Stability ◽  
Dimensional Surface

We study the possibility to explain the mystery of the dark matter (DM) through the transition from General Relativity to embedding gravity. This modification of gravity, which was proposed by Regge and Teitelboim, is based on a simple string-inspired geometrical principle: our spacetime is considered here as a four-dimensional surface in a flat bulk. We show that among the solutions of embedding gravity, there is a class of solutions equivalent to solutions of GR with an additional contribution of non-relativistic embedding matter, which can serve as cold DM. We prove the stability of such type of solutions and obtain an explicit form of the equations of motion of embedding matter in the non-relativistic limit. According to them, embedding matter turns out to have a certain self-interaction, which could be useful in the context of solving the core-cusp problem that appears in the [Formula: see text]CDM model.

Accelerated frames and galactic rotation curves

2019 ◽  
Vol 34 (27) ◽  
pp. 1950218
Author(s):  
S. C. Ulhoa ◽  
F. L. Carneiro
Keyword(s):  
Experimental Data ◽  
General Relativity ◽  
Dark Matter ◽  
Reference Frame ◽  
Rotation Curve ◽  
Reference Frames ◽  
Galactic Rotation ◽  
Inertial Reference Frame ◽  
Galactic Rotation Curve ◽  
Accelerated Frames

In this paper, the galactic rotation curve is analyzed as an effect of an accelerated reference frame. Such a rotation curve was the first evidence for the so-called dark matter. We show another possibility for this experimental data: non-inertial reference frame can fit the experimental curve. We also show that general relativity is not enough to completely explain that which encouraged alternatives paths such as the MOND approach. The accelerated reference frames hypothesis is well-suited to deal with the rotation curve of galaxies and perhaps has some role to play concerning other evidences for dark matter.

scholarly journals Dark matter in logarithmic F(R) gravity

2019 ◽  
Vol 28 (12) ◽  
pp. 1950157 ◽  
Author(s):  
Tomohiro Inagaki ◽  
Yamato Matsuo ◽  
Hiroki Sakamoto
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Modified Gravity ◽  
Field Method ◽  
Quantum Corrections ◽  
Prototype Model ◽  
Wide Range ◽  
Modified Gravity Theories ◽  
Primordial Inflation ◽  
Cmb Fluctuations

The logarithmic [Formula: see text]-corrected [Formula: see text] gravity is investigated as a prototype model of modified gravity theories with quantum corrections. By using the auxiliary field method, the model is described by the general relativity with a scalaron field. The scalaron field can be identified as an inflaton at the primordial inflation era. It is also one of the dark matter candidates in the dark energy (DE) era. It is found that a wide range of the parameters is consistent with the current observations of CMB fluctuations, DE and dark matter.

scholarly journals Compact stars in the pseudo-complex general relativity

2018 ◽  
Vol 1143 ◽  
pp. 012002
Author(s):  
C. A. Zen Vasconcellos ◽  
J. E. S. Costa ◽  
D. Hadjimichef ◽  
M. V. T. Machado ◽  
F. Köpp ◽  
...  
Keyword(s):  
General Relativity ◽  
Compact Stars ◽  
Complex General Relativity

scholarly journals Study of charged compact stars with class 1 metric under general relativity

2019 ◽  
Vol 97 (12) ◽  
pp. 1323-1331 ◽  
Author(s):  
S.K. Maurya ◽  
S. Roy Chowdhury ◽  
Saibal Ray ◽  
B. Dayanandan
Keyword(s):  
General Relativity ◽  
Compact Star ◽  
Space Time ◽  
Electron Cloud ◽  
Compact Stars ◽  
Stellar Structure ◽  
Spherically Symmetric ◽  
Class 1 ◽  
Maxwell Space ◽  
Physical Tests

In the present paper we study compact stars under the background of Einstein–Maxwell space–time, where the 4-dimensional spherically symmetric space–time of class 1 along with the Karmarkar condition has been adopted. The investigations, via the set of exact solutions, show several important results, such as (i) the value of density on the surface is finite; (ii) due to the presence of the electric field, the outer surface or the crust region can be considered to be made of electron cloud; (iii) the charge increases rapidly after crossing a certain cutoff region (r/R ≈ 0.3); and (iv) the avalanche of charge has a possible interaction with the particles that are away from the center. As the stellar structure supports all the physical tests performed on it, therefore the overall observation is that the model provides a physically viable and stable compact star.

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