scholarly journals Rippling 3-Riemannian structure describing gravity with dark matter effects

2021 ◽  
Author(s):  
Shivam S Naarayan

In an attempt to solve the missing mass problem, the paper introduces a probabilistic three-dimensional structure which is locally described by energy density, time density and a Riemannian metric. This proposition has its roots in the results of general relativity and quantum theory. On large scale, source mass binds energy density which causes curvature in the Riemannian manifold of space measure leading to variations in length and time scales. Additional gravitational effects are predicted for a source mass which are caused by the flow of bounded energy density and is proposed as a candidate for `dark matter' model. The paper makes testable predictions some of which may have already been observed as `dark matter' or `dark energy'.

1997 ◽  
Vol 12 (17) ◽  
pp. 1275-1282 ◽  
Author(s):  
M. Kawasaki ◽  
Naoshi Sugiyama ◽  
T. Yanagida

Gauge-mediated supersymmetry breaking models suggest the presence of the light gravitino with mass ~ 1 keV which can be warm dark matter in our universe. We consider large scale structure of the universe in the warm dark matter model and find that the power spectrum of the gravitino dark matter is almost the same as that of a cold dark matter at scales larger than about 1 Mpc. We also study the Ly α absorption systems which are presumed to be galaxies at high redshifts and show that the baryon density in the damped Ly α absorption systems predicted by the gravitino dark matter model is quite consistent with the present observation.


2011 ◽  
Vol 20 (08) ◽  
pp. 1471-1477
Author(s):  
KIN-WANG NG

Recent measurements of the large-scale cosmic microwave background anisotropy made by the Wilkinson Microwave Anisotropy Probe (WMAP) mission indicate a reflection asymmetry, an axis of evil, a low quadrupole, and a few multipoles deviated from predicted in the cold dark matter model with a cosmological constant. All of these may give us a hint about the physics of inflation during the first few e-folds or during the inflating period. Efforts taken along this direction will be reviewed and our recent work will be discussed.


2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Shuai Xu ◽  
Sibo Zheng

AbstractWe propose a decaying cold dark matter model to explain the excess of electron recoil observed at the XENON1T experiment. In this scenario, the daughter dark matter from the parent dark matter decay easily obtains velocity large enough to saturate the peak of the electron recoil energy around 2.5 keV, and the observed signal rate can be fulfilled by the parent dark matter with a mass of order 10–200 MeV and a lifetime larger than the age of Universe. We verify that this model is consistent with experimental limits from dark matter detections, Cosmic microwave background and large scale structure experiments.


2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Mario A. Rodríguez-Meza

We present a model of dark matter based on scalar-tensor theory of gravity. With this scalar field dark matter model we study the non-linear evolution of the large-scale structures in the universe. The equations that govern the evolution of the scale factor of the universe are derived together with the appropriate Newtonian equations to follow the nonlinear evolution of the structures. Results are given in terms of the power spectrum that gives quantitative information on the large-scale structure formation. The initial conditions we have used are consistent with the so-called concordance ΛCDM model.


2020 ◽  
Vol 501 (1) ◽  
pp. L71-L75
Author(s):  
Cornelius Rampf ◽  
Oliver Hahn

ABSTRACT Perturbation theory is an indispensable tool for studying the cosmic large-scale structure, and establishing its limits is therefore of utmost importance. One crucial limitation of perturbation theory is shell-crossing, which is the instance when cold-dark-matter trajectories intersect for the first time. We investigate Lagrangian perturbation theory (LPT) at very high orders in the vicinity of the first shell-crossing for random initial data in a realistic three-dimensional Universe. For this, we have numerically implemented the all-order recursion relations for the matter trajectories, from which the convergence of the LPT series at shell-crossing is established. Convergence studies performed at large orders reveal the nature of the convergence-limiting singularities. These singularities are not the well-known density singularities at shell-crossing but occur at later times when LPT already ceased to provide physically meaningful results.


2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Zexi Hu ◽  
Chengfeng Cai ◽  
Yi-Lei Tang ◽  
Zhao-Huan Yu ◽  
Hong-Hao Zhang

Abstract We propose a vector dark matter model with an exotic dark SU(2) gauge group. Two Higgs triplets are introduced to spontaneously break the symmetry. All of the dark gauge bosons become massive, and the lightest one is a viable vector DM candidate. Its stability is guaranteed by a remaining Z2 symmetry. We study the parameter space constrained by the Higgs measurement data, the dark matter relic density, and direct and indirect detection experiments. We find numerous parameter points satisfying all the constraints, and they could be further tested in future experiments. Similar methodology can be used to construct vector dark matter models from an arbitrary SO(N) gauge group.


Author(s):  
Jiajun Zhang ◽  
Hantao Liu ◽  
Ming-Chung Chu

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