scholarly journals Dark Matter Creation and Anti-Gravity Acceleration of the Expanding Universe

2021 ◽  
Vol 12 (03) ◽  
pp. 139-160
Author(s):  
F. C. Hoh
Keyword(s):  
Dark Matter ◽  
Expanding Universe ◽  
Matter Creation ◽  
Gravity Acceleration

scholarly journals FIMP Dark Matter from Leptogenesis in Fast Expanding Universe

2021 ◽  
Vol 2021 (06) ◽  
pp. 006
Author(s):  
Zhi-Fang Chang ◽  
Zhao-Xuan Chen ◽  
Jia-Shu Xu ◽  
Zhi-Long Han
Keyword(s):  
Dark Matter ◽  
Expanding Universe

scholarly journals Modelling the Large Scale Structure of the Universe after COBE

1995 ◽  
Vol 48 (6) ◽  
pp. 1083 ◽  
Author(s):  
PJ Quinn
Keyword(s):  
Dark Matter ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Expanding Universe ◽  
Model Predictions ◽  
Perturbation Spectrum ◽  
The Universe

N-body models running on supercomputers have been widely used to explore the development of structure in the expanding Universe. Recent results from the COBE satellite have provided a global normalisation of these models which now allows detailed comparisons to be drawn between observations and model predictions. Some predictions of the cold dark matter primordial perturbation spectrum are now shown to be consistent with surveys of galaxy redshifts.

scholarly journals Dynamics of dark energy in collapsing halo of dark matter

2015 ◽  
Vol 5 (1) ◽  
pp. 51-56 ◽  
Author(s):  
M. Tsizh ◽  
B. Novosyadlyj
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Large Scale ◽  
Einstein Equations ◽  
Linear Stage ◽  
Expanding Universe ◽  
Simple Method ◽  
Linear Evolution ◽  
Non Linear ◽  
Linear Differential

We investigate the non-linear evolution of spherical density and velocity perturbations of dark matter and dark energy in the expanding Universe. For this we have used the conservation and Einstein equations to describe the evolution of gravitationally coupled inhomogeneities of dark matter, dark energy and radiation from the linear stage in the early Universe to the non-linear stage at the current epoch. A simple method of numerical integration of the system of non-linear differential equations for evolution of the central part of halo is proposed. The results are presented for the halo of cluster (k=2 Mpc-1) and supercluster scales (k=0.2 Mpc-1) and show that a quintessential scalar field dark energy with a low value of effective speed of sound cs<0.1 can have a notable impact on the formation of large-scale structures in the expanding Universe.

scholarly journals Irreversible Thermodynamic Description of Dark Matter and Radiation Creation during Inflationary Reheating

2017 ◽  
Vol 2017 ◽  
pp. 1-24 ◽  
Author(s):  
Juntong Su ◽  
Tiberiu Harko ◽  
Shi-Dong Liang
Keyword(s):  
Dark Matter ◽  
Scalar Field ◽  
Particle Production ◽  
Thermodynamic Description ◽  
Cosmological Parameters ◽  
Field Energy ◽  
Field Equations ◽  
Matter Creation ◽  
The Universe ◽  
Relativistic Matter

We investigate matter creation processes during the reheating period of the early Universe, by using the thermodynamic of open systems. The Universe is assumed to consist of the inflationary scalar field, which, through its decay, generates relativistic matter and pressureless dark matter. The inflationary scalar field transfers its energy to the newly created matter particles, with the field energy decreasing to near zero. The equations governing the irreversible matter creation are obtained by combining the thermodynamics description of the matter creation and the gravitational field equations. The role of the different inflationary scalar field potentials is analyzed by using analytical and numerical methods. The values of the energy densities of relativistic matter and dark matter reach their maximum when the Universe is reheated up to the reheating temperature, which is obtained as a function of the scalar field decay width, the scalar field particle mass, and the cosmological parameters. Particle production leads to the acceleration of the Universe during the reheating phase, with the deceleration parameter showing complex dynamics. Once the energy density of the scalar field becomes negligible with respect to the matter densities, the expansion of the Universe decelerates, and inflation has a graceful exit.

scholarly journals A bound system in the expanding universe with modified holographic Ricci dark energy and dark matter

2014 ◽  
Vol 355 (1) ◽  
pp. 187-193 ◽  
Author(s):  
En-Kun Li ◽  
Yu Zhang ◽  
Jin-Ling Geng ◽  
Peng-Fei Duan
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Expanding Universe ◽  
Ricci Dark Energy

scholarly journals Constraints on the Dark Side of the Universe and Observational Hubble Parameter Data

2010 ◽  
Vol 2010 ◽  
pp. 1-14 ◽  
Author(s):  
Tong-Jie Zhang ◽  
Cong Ma ◽  
Tian Lan
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Hubble Parameter ◽  
Future Prospect ◽  
Cosmological Models ◽  
Dark Side ◽  
Expanding Universe ◽  
Basic Principles ◽  
The Universe

This paper is a review on the observational Hubble parameter data that have gained increasing attention in recent years for their illuminating power on the dark side of the universe: the dark matter, dark energy, and the dark age. Currently, there are two major methods of independent observationalH(z)measurement, which we summarize as the “differential age method” and the “radial BAO size method.” Starting with fundamental cosmological notions such as the spacetime coordinates in an expanding universe, we present the basic principles behind the two methods. We further review the two methods in greater detail, including the source of errors. We show how the observationalH(z)data present itself as a useful tool in the study of cosmological models and parameter constraint, and we also discuss several issues associated with their applications. Finally, we point the reader to a future prospect of upcoming observation programs that will lead to some major improvements in the quality of observationalH(z)data.

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