scholarly journals Five-Dimensional anisotropic Dark energy Cosmological model in the presence of Scalar-Meson fields in General relativity

2019 ◽  
Vol 1 (2) ◽  
pp. 67-70 ◽  
Author(s):  
DRK Reddy ◽  
G Ramesh
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Cosmological Model ◽  
Scalar Meson ◽  
Anisotropic Dark Energy

A UNIFIED DARK ENERGY MODEL FROM A VANISHING SPEED OF SOUND WITH EMERGENT COSMOLOGICAL CONSTANT

2014 ◽  
Vol 23 (02) ◽  
pp. 1450012 ◽  
Author(s):  
ORLANDO LUONGO ◽  
HERNANDO QUEVEDO
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Cosmological Model ◽  
Cosmological Constant ◽  
Energy Budget ◽  
Speed Of Sound ◽  
Dark Energy Model ◽  
Vacuum Energy ◽  
Cosmic Acceleration ◽  
Energy Term

The problem of the cosmic acceleration is here revisited by using the fact that the adiabatic speed of sound can be assumed to be negligible small. Within the context of general relativity, the total energy budget is recovered under the hypothesis of a vanishing speed of sound by assuming the existence of one fluid only. We find a cosmological model which reproduces the main results of the ΛCDM paradigm at late-times, showing an emergent cosmological constant, which is not at all related with the vacuum energy term. As a consequence, the model presented here behaves as a unified dark energy (DE) model.

scholarly journals LRS Bianchi Type-I Cosmological Model with Anisotropic Dark Energy and Special Form of Deceleration Parameter

2013 ◽  
Vol 04 (08) ◽  
pp. 1037-1040 ◽  
Author(s):  
Kishor Shankarrao Adhav ◽  
Rajesh Purushottam Wankhade ◽  
Abhijit Shankarrao Bansod
Keyword(s):  
Dark Energy ◽  
Cosmological Model ◽  
Deceleration Parameter ◽  
Special Form ◽  
Bianchi Type ◽  
Type I ◽  
Bianchi Type I ◽  
Anisotropic Dark Energy

scholarly journals Can a negative-mass cosmology explain dark matter and dark energy?

2019 ◽  
Vol 626 ◽  
pp. A5 ◽  
Author(s):  
H. Socas-Navarro
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Dark Energy ◽  
Cosmological Model ◽  
Large Scale ◽  
Dark Matter Halos ◽  
Challenging Problem ◽  
Speed Of Light ◽  
Negative Mass ◽  
Galactic Dark Matter

A recent study by Farnes (2018, A&A, 620, A92) proposed an alternative cosmological model in which both dark matter and dark energy are replaced with a single fluid of negative mass. This paper presents a critical review of that model. A number of problems and discrepancies with observations are identified. For instance, the predicted shape and density of galactic dark matter halos are incorrect. Also, halos would need to be less massive than the baryonic component, otherwise they would become gravitationally unstable. Perhaps the most challenging problem in this theory is the presence of a large-scale version of the “runaway effect”, which would result in all galaxies moving in random directions at nearly the speed of light. Other more general issues regarding negative mass in general relativity are discussed, such as the possibility of time-travel paradoxes.

scholarly journals Dark Energy and Cosmological Model

2020 ◽  
Vol 10 (2) ◽  
Author(s):  
Radhika Deshmukh
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Dark Energy ◽  
Cosmological Model ◽  
Empty Space ◽  
Space Time ◽  
Astronomical Observation ◽  
Quantum Level ◽  
Recent Modification ◽  
Time Expansion

Today the space of our universe is filled with invisible stuff matter which expanding under the action of gravity which was dark matter. In 1990’s astronomical observation and theoretical calculation was leading astrophysicists to believe that not only the dark matter but also there is vacuum empty space filled in universe that is dark energy. It is suggested that the apparently disparate cosmological phenomenon attributed to so called “dark matter” and dark energy arise from quantum level of space -time itself. This creation of space time results in metric expansion. A recent modification of Einstein’s theory of general relativity by Chadwick, Hodgkinson and McDonald incorporate space time expansion. Recent evidence predicts that apparent amount of dark matter increases with age of universe. In addition proposal leads to the same result for the small but non-vanishing cosmological constant, related to dark energy.

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