scholarly journals DOES ENTROPIC GRAVITY BOUND THE MASSES OF THE PHOTON AND GRAVITON?

2011 ◽  
Vol 26 (03) ◽  
pp. 171-181 ◽  
Author(s):  
J. R. MUREIKA ◽  
R. B. MANN
Keyword(s):  
Black Holes ◽  
Test Particle ◽  
Information Transfer ◽  
Local Symmetry ◽  
Speed Of Light ◽  
M 10 ◽  
Entropic Gravity ◽  
Holographic Screen ◽  
The Masses ◽  
The Universe

If the information transfer between test particle and holographic screen in entropic gravity respects both the uncertainty principle and causality, a lower limit on the number of bits in the universe relative to its mass may be derived. Furthermore, these limits indicate particles that putatively travel at the speed of light — the photon and/or graviton — have a nonzero mass m ≥10-68 kg . This result is found to be in excellent agreement with current experimental mass bounds on the graviton and photon, suggesting that entropic gravity may be the result of a (recent) softly-broken local symmetry. Stronger bounds emerge from consideration of ultradense matter such as neutron stars, yielding limits of m ≥10-48–10-50 kg , barely within the experimental photon range and outside that of the graviton. We find that for black holes these criteria cannot be satisfied, and suggest some possible implications of this result.

Beyond the Schwarzschild Metric

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Waves ◽  
Test Particle ◽  
Direct Detection ◽  
Relativistic Effects ◽  
Big Bang ◽  
Clusters Of Galaxies ◽  
General Relativistic ◽  
The Universe

General relativity explains much more than the spacetime around static spherical masses.We briefly assess general relativity in the larger context of physical theories, then explore various general relativistic effects that have no Newtonian analog. First, source massmotion gives rise to gravitomagnetic effects on test particles.These effects also depend on the velocity of the test particle, which has substantial implications for orbits around black holes to be further explored in Chapter 20. Second, any changes in the sourcemass ripple outward as gravitational waves, and we tell the century‐long story from the prediction of gravitational waves to their first direct detection in 2015. Third, the deflection of light by galaxies and clusters of galaxies allows us to map the amount and distribution of mass in the universe in astonishing detail. Finally, general relativity enables modeling the universe as a whole, and we explore the resulting Big Bang cosmology.

scholarly journals Gravitational Waves from Compact Bodies

1996 ◽  
Vol 165 ◽  
pp. 153-183
Author(s):  
Kip S. Thorne
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Neutron Stars ◽  
Gravitational Radiation ◽  
Relativity Theory ◽  
Energy Concentration ◽  
Speed Of Light ◽  
General Relativity Theory ◽  
Concentration Changes ◽  
The Universe

According to general relativity theory, compact concentrations of energy (e.g., neutron stars and black holes) should warp spacetime strongly, and whenever such an energy concentration changes shape, it should create a dynamically changing spacetime warpage that propagates out through the Universe at the speed of light. This propagating warpage is called gravitational radiation — a name that arises from general relativity's description of gravity as a consequence of spacetime warpage.

scholarly journals Black holes in the varying speed of light theory

2007 ◽  
Vol 85 (12) ◽  
pp. 1409-1415
Author(s):  
H Shojaie ◽  
M Farhoudi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Primordial Black Holes ◽  
Speed Of Light ◽  
Schwarzschild Solution ◽  
Charged Black Holes ◽  
The Universe ◽  
Light Theory ◽  
Schwarzschild Horizon ◽  
Schwarzschild Radius

We consider the effect of the varying speed of light theory on nonrotating black holes. We show that in any varying-c theory, the Schwarzschild solution is neither static nor stationary. For a no-charged black hole, the singularity in the Schwarzschild horizon cannot be removed by coordinate transformation. Hence, no matter can enter the horizon, and the interior part of the black hole is separated from the rest of the Universe. If ċ < 0, then the size of the Schwarzschild radius increases with time. The higher value of the speed of light in the very early Universe may have caused a large reduction in the probability of the creation of the primordial black holes and their population. The same analogy is also considered for charged black holes. PACS No.: 04.70.–s

scholarly journals Entropic gravity from noncommutative black holes

2017 ◽  
Vol 15 (01) ◽  
pp. 1850004 ◽  
Author(s):  
Rafael C. Nunes ◽  
Hooman Moradpour ◽  
Edésio M. Barboza ◽  
Everton M. C. Abreu ◽  
Jorge Ananias Neto
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Field ◽  
Cosmological Constant ◽  
Black Hole Entropy ◽  
Space Time ◽  
Isotropic Universe ◽  
Entropic Gravity ◽  
The Universe

In this paper, we investigated the effects of a noncommutative (NC) space-time on the dynamics of the Universe. We generalize the black hole entropy for a NC black hole. Then, using the entropic gravity formalism, we will show that the noncommutativity changes the strength of the gravitational field. By applying this result to a homogeneous and isotropic Universe containing nonrelativistic matter and a cosmological constant, we show that the modified scenario by the noncommutativity of the space-time is a better fit to the obtained data than the standard one at 68% CL.

scholarly journals INTERMEDIATE-MASS BLACK HOLES

2004 ◽  
Vol 13 (01) ◽  
pp. 1-64 ◽  
Author(s):  
M. COLEMAN MILLER ◽  
E. J. M. COLBERT
Keyword(s):  
Black Holes ◽  
Theoretical Work ◽  
Core Collapse ◽  
Stellar Clusters ◽  
Intermediate Mass ◽  
Fundamental Physics ◽  
The Core ◽  
M 10 ◽  
The Universe ◽  
Intermediate Mass Black Holes

The mathematical simplicity of black holes, combined with their links to some of the most energetic events in the universe, means that black holes are key objects for fundamental physics and astrophysics. Until recently, it was generally believed that black holes in nature appear in two broad mass ranges: stellar-mass (M~3–20 M⊙), which are produced by the core collapse of massive stars, and supermassive (M~106–1010 M⊙), which are found in the centers of galaxies and are produced by a still uncertain combination of processes. In the last few years, however, evidence has accumulated for an intermediate-mass class of black holes, with M~102–104 M⊙. If such objects exist they have important implications for the dynamics of stellar clusters, the formation of supermassive black holes, and the production and detection of gravitational waves. We review the evidence for intermediate-mass black holes and discuss future observational and theoretical work that will help clarify numerous outstanding questions about these objects.

scholarly journals Effects of bosonic and fermionic q-deformation on the entropic gravity

2019 ◽  
Vol 34 (31) ◽  
pp. 1950249
Author(s):  
Salih Kibaroğlu ◽  
Mustafa Senay
Keyword(s):  
Black Holes ◽  
Poisson Equation ◽  
Entropic Force ◽  
Fundamental Interaction ◽  
Field Equations ◽  
The Poisson Equation ◽  
Entropic Gravity ◽  
Holographic Screen ◽  
Fermion Gas ◽  
Law Of Gravity

In this paper, we study thermodynamical contributions to the theory of gravity under the q-deformed boson and fermion gas models. According to Verlinde’s proposal, the law of gravity is not based on a fundamental interaction but it emerges as an entropic force from the changes of entropy associated with the information on the holographic screen. In addition, Strominger shows that the extremal quantum black holes obey neither boson nor fermion statistics, but they obey deformed statistic. Using these notions, we find q-deformed entropy and temperature functions. We also present the contributions that come from the q-deformed model to the Poisson equation, Newton’s law of gravity and Einstein’s field equations.

scholarly journals Explanation of the huge difference between vacuum energy and dark energy in the theory of the dynamic medium of reference

2021 ◽  
Vol 34 (1) ◽  
pp. 61-67
Author(s):  
Olivier Pignard
Keyword(s):  
Black Holes ◽  
Dark Energy ◽  
Quantum Entanglement ◽  
Vacuum Energy ◽  
Speed Of Light ◽  
Distant Galaxies ◽  
Planck Time ◽  
The Universe ◽  
Schwarzschild Radius

The object of this article is to present the vacuum energy and the dark energy within the framework of the theory of the dynamic medium of reference and to explain the phenomenal difference between the two energies. The dynamic medium is made up of entities (called gravitons) whose vectorial average of speed determines the speed of the flux of the medium at each point in space. It is shown that inside the horizon of black holes (defined by the Schwarzschild radius), the speed of flux is greater than the speed of light, which means that the gravitons themselves have a higher speed to that of light. The quantum entanglement of two photons which propagate in two opposite directions is due to a connection made by gravitons. It is therefore proposed that the gravitons move at the speed <mml:math display="inline"> <mml:mrow> <mml:msub> <mml:mi>V</mml:mi> <mml:mi>G</mml:mi> </mml:msub> <mml:mo>≈</mml:mo> <mml:mfrac> <mml:mrow> <mml:msub> <mml:mi>R</mml:mi> <mml:mrow> <mml:mtext>universe</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> <mml:mrow> <mml:msub> <mml:mi>t</mml:mi> <mml:mrow> <mml:mtext>Planck</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> </mml:mfrac> </mml:mrow> </mml:math> ≈ 2.4 × 1069 m/s, which makes it possible to guarantee the entanglement of the two photons whatever their position in the Universe and the impossibility to measure the time taken by the influence of a photon to arrive at its twin photon because it is less than the Planck time t Planck. The expression of the vacuum energy and that of the dark energy within the framework of the theory of the dynamic medium of reference is established. The two expressions E vacuum and E dark and the value of the speed of the most distant galaxies V galaxy make it possible to calculate an approximate value of the speed of the gravitons <mml:math display="inline"> <mml:msub> <mml:mrow> <mml:mi>V</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>G</mml:mi> </mml:mrow> </mml:msub> <mml:mo>≈</mml:mo> <mml:msub> <mml:mrow> <mml:mi>V</mml:mi> </mml:mrow> <mml:mrow> <mml:mtext mathvariant="normal">galaxy</mml:mtext> </mml:mrow> </mml:msub> <mml:msqrt> <mml:mfrac> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>E</mml:mi> </mml:mrow> <mml:mrow> <mml:mtext mathvariant="normal">vacuum</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>E</mml:mi> </mml:mrow> <mml:mrow> <mml:mtext mathvariant="normal">dark</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> </mml:mfrac> </mml:msqrt> </mml:math> ≈ 2.8 × 1069 m/s. This value of the speed of the graviton is very close to that obtained by the quantum entanglement of two photons, which reinforces the existence of nonmaterial entities going at these phenomenal speeds.

scholarly journals PSEUDO-NEWTONIAN GRAVITATIONAL POTENTIAL FOR SCHWARZSCHILD–DE SITTER SPACE–TIMES

2008 ◽  
Vol 17 (11) ◽  
pp. 2089-2105 ◽  
Author(s):  
ZDENĚK STUCHLÍK ◽  
JIŘÍ KOVÁŘ
Keyword(s):  
Black Holes ◽  
Gravitational Field ◽  
Accretion Disks ◽  
Gravitational Potential ◽  
Test Particle ◽  
De Sitter Space ◽  
Spherically Symmetric ◽  
De Sitter ◽  
General Relativistic ◽  
The Universe

Pseudo-Newtonian gravitational potential describing the gravitational field of static and spherically symmetric black holes in the universe with a repulsive cosmological constant is introduced. In order to demonstrate the accuracy of the pseudo-Newtonian approach, the related effective potential for test particle motion is constructed and compared with its general-relativistic counterpart given by the Schwarzschild–de Sitter geometry. The results indicate that such an approach could be useful in applications of developed Newtonian theories of accretion disks in astrophysically interesting situations in large galactic structures for the Schwarzschild–de Sitter space–times with the cosmological parameter y = Λ M2/3 ≤ 10-6.

Black holes in the Universe

2001 ◽  
Vol 171 (3) ◽  
pp. 307 ◽  
Author(s):  
Igor D. Novikov ◽  
Valerii P. Frolov
Keyword(s):  
Black Holes ◽  
The Universe

INFLATION, QUINTESSENCE PROBLEM AND VARYING SPEED OF LIGHT

2002 ◽  
Vol 17 (05) ◽  
pp. 295-302
Author(s):  
SUBENOY CHAKRABORTY
Keyword(s):  
Cosmological Constant ◽  
Accelerated Expansion ◽  
Speed Of Light ◽  
Expansion Of The Universe ◽  
The Universe

In this paper it is shown that the present accelerated expansion of the Universe can be explained only by considering variation of the speed of light, without taking into account the cosmological constant or quintessence matter.

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