scholarly journals The holographic spacetime model of cosmology

2018 ◽  
Vol 27 (14) ◽  
pp. 1846005 ◽  
Author(s):  
Tom Banks ◽  
W. Fischler
Keyword(s):  
Dark Matter ◽  
Gravitational Waves ◽  
Structure Formation ◽  
Big Bang ◽  
Baryon Asymmetry ◽  
Gaussian Fluctuations ◽  
Primordial Gravitational Waves ◽  
Conventional Models ◽  
Non Gaussian ◽  
The Big Bang

This essay outlines the Holographic Spacetime (HST) theory of cosmology and its relation to conventional theories of inflation. The predictions of the theory are compatible with observations, and one must hope for data on primordial gravitational waves or non-Gaussian fluctuations to distinguish it from conventional models. The model predicts an early era of structure formation, prior to the Big Bang. Understanding the fate of those structures requires complicated simulations that have not yet been done. The result of those calculations might falsify the model, or might provide a very economical framework for explaining dark matter and the generation of the baryon asymmetry.

Origins of Gravitational Waves and Detectors

2020 ◽  
pp. 88-107
Author(s):  
John W. Moffat
Keyword(s):  
Black Holes ◽  
Neutron Stars ◽  
Gravitational Waves ◽  
Radio Telescope ◽  
Big Bang ◽  
Gravity Theory ◽  
Primordial Gravitational Waves ◽  
The Big Bang ◽  
The Waves

Civita criticized Einstein’s papers on gravitational waves: their energy momentum is frame dependent and therefore does not fit the covariance of Einstein’s gravity theory. Infeld and Rosen did not believe gravitational waves existed, and Einstein changed his mind on their existence repeatedly. Others did believe in them, such as Fock and Feynman. Weber constructed his “Weber bar” to detect gravitational waves, but when he claimed success, he was criticized. He then proposed using a Michelson-Morley type of interferometer with lasers to detect gravitational waves, as did Weiss. Merging black holes and neutron stars were proposed as detectable sources of gravitational waves. Taylor and Hulse, using the large Arecibo radio telescope, indirectly detected gravitational waves from inspiraling neutron stars. Primordial gravitational waves, still emanating from the Big Bang, were claimed to have been detected by BICEP2, but the waves were eventually shown to be a result of foreground dust.

scholarly journals STRUCTURE FORMATION WITH MIRROR DARK MATTER: CMB AND LSS

2005 ◽  
Vol 14 (01) ◽  
pp. 107-119 ◽  
Author(s):  
ZURAB BEREZHIANI ◽  
PAOLO CIARCELLUTI ◽  
DENIS COMELLI ◽  
FRANCESCO L. VILLANTE
Keyword(s):  
Dark Matter ◽  
Structure Formation ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Big Bang ◽  
Dark Matter Candidate ◽  
Microwave Background ◽  
Quantitative Calculation ◽  
World Hypothesis ◽  
The Big Bang

In the mirror world hypothesis, the mirror baryonic component emerges as a possible dark matter candidate. An immediate question arises: how do the mirror baryons behave and what are their differences from the more familiar dark matter candidates such as cold dark matter? In this paper, we answer this question quantitatively. First, we discuss the dependence of the relevant scales for the structure formation (Jeans and Silk scales) on the two macroscopic parameters necessary to define the model: the temperature of the mirror plasma (limited by the Big Bang Nucleosynthesis) and the amount of mirror baryonic matter. Then we perform a complete quantitative calculation of the implications of mirror dark matter on the cosmic microwave background and large scale structure power spectrum. Finally, confronting with the present observational data, we obtain some bounds on the mirror parameter space.

scholarly journals An Origami Approximation to the Cosmic Web

2014 ◽  
Vol 11 (S308) ◽  
pp. 97-102 ◽  
Author(s):  
Mark C. Neyrinck
Keyword(s):  
Dark Matter ◽  
Phase Space ◽  
Structure Formation ◽  
Big Bang ◽  
Velocity Fields ◽  
Spin Correlations ◽  
Convex Polyhedral ◽  
Nearby Galaxies ◽  
The Big Bang ◽  
First Time

AbstractThe powerful Lagrangian view of structure formation was essentially introduced to cosmology by Zel'dovich. In the current cosmological paradigm, a dark-matter-sheet 3D manifold, inhabiting 6D position-velocity phase space, was flat (with vanishing velocity) at the big bang. Afterward, gravity stretched and bunched the sheet together in different places, forming a cosmic web when projected to the position coordinates.Here, I explain some properties of an origami approximation, in which the sheet does not stretch or contract (an assumption that is false in general), but is allowed to fold. Even without stretching, the sheet can form an idealized cosmic web, with convex polyhedral voids separated by straight walls and filaments, joined by convex polyhedral nodes. The nodes form in ‘polygonal’ or ‘polyhedral’ collapse, somewhat like spherical/ellipsoidal collapse, except incorporating simultaneous filament and wall formation. The origami approximation allows phase-space geometries of nodes, filaments, and walls to be more easily understood, and may aid in understanding spin correlations between nearby galaxies. This contribution explores kinematic origami-approximation models giving velocity fields for the first time.

Black Holes

2021 ◽  
pp. 53-65
Author(s):  
Gianfranco Bertone
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Dark Energy ◽  
Gravitational Waves ◽  
Nuclear Fuel ◽  
Big Bang ◽  
The Sun ◽  
Modern Physics ◽  
The Big Bang ◽  
The Universe

In the second part of the book, I argue that the four biggest mysteries of modern physics and astronomy—dark matter, dark energy, black holes, and the Big Bang—sink their roots into the physics of the infinitely small. And I argue that gravitational waves may shed new light on, and possibly solve, each of these four mysteries. I start here by introducing the problem of dark matter, the mysterious substance that permeates the Universe at all scales and describe the gravitational waves observations that might soon elucidate its nature. The next time you see the Sun shining in the sky, consider this: what blinds your eyes and warms your skin is an immense nuclear furnace, which transforms millions of tons of nuclear fuel into energy every second. And when you contemplate the night sky, try to visualize it for what it essentially is: an endless expanse of colossal natural reactors, forging the atoms that we, and everything that surrounds us, are made of.

PRIMORDIAL GRAVITATIONAL WAVES AND INFLATION: POSSIBILITIES FOR DETECTION

2005 ◽  
Vol 20 (33) ◽  
pp. 2503-2519 ◽  
Author(s):  
ASANTHA COORAY
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Large Scale ◽  
Rapid Evolution ◽  
Big Bang ◽  
Primordial Gravitational Waves ◽  
Cmb Polarization ◽  
Density Perturbations ◽  
Merger Rate ◽  
The Big Bang

The curl-modes of Cosmic Microwave Background (CMB) polarization probe horizon-scale primordial gravitational waves related to inflation. A significant source of confusion is expected from a lensing conversion of polarization related to density perturbations to the curl mode, during the propagation of photons through the large scale structure. Either high resolution CMB anisotropy observations or 21 cm fluctuations at redshifts 30 and higher can be used to delens polarization data and to separate gravitational-wave polarization signature from that of cosmic-shear related signal. Separations based on proposed lensing reconstruction techniques for reasonable future experiments allow the possibility to probe inflationary energy scales down to 1015 GeV . Beyond CMB polarization, at frequencies between 0.01 Hz to 1 Hz, space-based laser interferometers can also be used to probe the inflationary gravitational wave background. The confusion here is related to the removal of merging neutron star binaries at cosmological distances. Given the low merger rate and the rapid evolution of the gravitational wave frequency across this band, reliable removal techniques can be constructed. We discuss issues related to joint constraints that can be placed on the inflationary models based on CMB polarization information and space-based interferometers such as the Big Bang Observer.

scholarly journals Turbulent Mixing, Viscosity, Diffusion, and Gravity in the Formation of Cosmological Structures: The Fluid Mechanics of Dark Matter

2000 ◽  
Vol 122 (4) ◽  
pp. 830-835 ◽  
Author(s):  
C. H. Gibson
Keyword(s):  
Dark Matter ◽  
Fluid Mechanics ◽  
Structure Formation ◽  
Galaxy Cluster ◽  
Small Mass ◽  
Big Bang ◽  
Neutral Gas ◽  
In The Beginning ◽  
The Big Bang ◽  
Baryonic Dark Matter

Self-gravitational structure formation theory for astrophysics and cosmology is revised using nonlinear fluid mechanics. Gibson’s 1996–2000 theory balances fluid mechanical forces with gravitational forces and density diffusion with gravitational diffusion at critical viscous, turbulent, magnetic, and diffusion length scales termed Schwarz scales. Condensation and fragmentation occur for scales exceeding the largest Schwarz scale rather than LJ, the length scale introduced by Jeans in his 1902 inviscid-linear-acoustic theory. The largest Schwarz scale is often larger or smaller than LJ. From the new theory, the inner-halo 1021 m dark-matter of galaxies comprises ∼105fossil-LJ-scale clumps of 1012 Earth-mass fossil-LSV-scale planets called primordial fog particles (PFPs) condensed soon after the cooling transition from plasma to neutral gas, 300,000 years after the Big Bang, with PFPs tidally disrupted from their clumps forming the interstellar medium. PFPs explain Schild’s 1996 “rogue planets…likely to be the missing mass” of a quasar lens-galaxy, inferred from twinkling frequencies of the quasar mirages, giving 30 million planets per star. The non-baryonic dark matter is super-diffusive and fragments at large LSD scales to form massive outer-galaxy-halos. In the beginning of structure formation 30,000 years after the Big Bang, with photon viscosity values ν of 5×1026 m2 s−1, the viscous Schwarz scale matched the horizon scale LSV≈LH<LJ, giving 1046 kg proto-superclusters and finally 1042 kg proto-galaxies. Non-baryonic fluid diffusivities D∼1028 m2 s−1 from galaxy-outer-halo LSD scales 1022 m measured in a dense galaxy cluster by Tyson, J. A., and Fischer, P., 1995, “Measurement of the Mass profile of Abell 1689,” Ap. J., 446, pp. L55–L58, indicate non-baryonic dark matter particles must have small mass ∼10−35 kg to avoid detection. [S0098-2202(00)01504-2]

scholarly journals Dynamo effects in gravity

2019 ◽  
Vol 127 ◽  
pp. 02009
Author(s):  
Boris Shevtsov
Keyword(s):  
Gravitational Constant ◽  
Nonlinear Oscillations ◽  
Big Bang ◽  
Baryon Asymmetry ◽  
System Of Equations ◽  
Fractal Structures ◽  
Expansion Of The Universe ◽  
The Big Bang ◽  
The Universe ◽  
Made In

Nonlinear oscillations in the dynamic system of gravitational and material fields are considered. The problems of singularities and caustics in gravity, expansion and baryon asymmetry of the Universe, wave prohibition of collapse into black holes, and failure of the Big Bang concept are discussed. It is assumed that the effects of the expansion of the Universe are coupling with the reverse collapse of dark matter. This hypothesis is used to substantiate the vortex and fractal structures in the distribution of matter. A system of equations is proposed for describing turbulent and fluctuation processes in gravitational and material fields. Estimates of the di usion parameters of such a system are made in comparison with the gravitational constant.

Gravitational waves: A probe to the physics in the early universe

2015 ◽  
Vol 30 (28n29) ◽  
pp. 1545005
Author(s):  
Qing-Guo Huang
Keyword(s):  
Quantum Theory ◽  
Gravitational Waves ◽  
Early Universe ◽  
Upper Bound ◽  
Planck Scale ◽  
Big Bang ◽  
Planck Data ◽  
Inflationary Scenario ◽  
Fundamental Scale ◽  
The Big Bang

Gravitational waves can escape from the big bang and can be taken as a probe to the physics, in particular the inflation, in the early universe. Planck scale is a fundamental scale for quantum theory of gravity. Requiring the excursion distance of inflaton in the field space during inflation yields an upper bound on the tensor-to-scalar ratio. For example, [Formula: see text] for [Formula: see text]. In the typical inflationary scenario, we predict [Formula: see text] and [Formula: see text] which are consistent with Planck data released in 2015 quite well. Subtracting the contribution of thermal dust measured by Planck, BICEP2 data implies [Formula: see text] which is the tightest bound on the tensor-to-scalar ratio from current experiments.

scholarly journals Connecting cosmological simulations to the real world

2003 ◽  
Vol 208 ◽  
pp. 245-260
Author(s):  
C.S. Frenk
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Big Bang ◽  
Accelerated Expansion ◽  
Astronomical Data ◽  
Cosmic Evolution ◽  
Small Quantum ◽  
The Big Bang ◽  
Current Paradigm ◽  
Coherent Picture

A timely combination of new theoretical ideas and observational discoveries has brought about significant advances in our understanding of cosmic evolution. Computer simulations have played a key role in these developments by providing the means to interpret astronomical data in the context of physical and cosmological theory. In the current paradigm, our Universe has a flat geometry, is undergoing accelerated expansion and is gravitationaly dominated by elementary particles that make up cold dark matter. Within this framework, it is possible to simulate in a computer the emergence of galaxies and other structures from small quantum fluctuations imprinted during an epoch of inflationary expansion shortly after the Big Bang. The simulations must take into account the evolution of the dark matter as well as the gaseous processes involved in the formation of stars and other visible components. Although many unresolved questions remain, a coherent picture for the formation of cosmic structure in now beginning to emerge.

A classical non-quantum all-time time-symmetrical zero-energy single-bounce model for the creation, big bang, and death of the universe

2019 ◽  
Vol 28 (14) ◽  
pp. 1944024 ◽  
Author(s):  
Arthur E. Fischer
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Big Bang ◽  
Final States ◽  
Level Curve ◽  
Zero Energy ◽  
Time Model ◽  
Gravitational Effects ◽  
The Big Bang ◽  
The Universe

In this paper, we show how the [Formula: see text]CDM (Lambda Cold Dark Matter) Standard Model for cosmology can be extrapolated backwards through the big bang into the infinite past to yield an all-time model of the universe with scale factor given by [Formula: see text] defined and continuous for all [Formula: see text] and smooth ([Formula: see text] and satisfying Friedmann’s equation for all [Formula: see text]. At the big bang [Formula: see text], there is a nondifferentiable cusp singularity and our model shows some details of the behavior of the universe at this singularity. Our model is a zero-energy single-bounce model and an examination of the [Formula: see text]-plot of the [Formula: see text] level curve gives critical information about the initial and final states of the universe, about the evolution of the universe, and about the behavior of the universe at the big bang. Our results show that much can be said classically about the birth, big bang and death of the universe before one needs to reach for quantum gravitational effects.

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