scholarly journals Testing the equivalence principle via the shadow of black holes

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Sheng-Feng Yan ◽  
Chunlong Li ◽  
Lingqin Xue ◽  
Xin Ren ◽  
Yi-Fu Cai ◽  
...  
Keyword(s):  
Black Holes ◽  
Equivalence Principle

Black hole fusion made easy

2016 ◽  
Vol 25 (12) ◽  
pp. 1644015
Author(s):  
Roberto Emparan ◽  
Marina Martínez
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Event Horizon ◽  
Critical Behavior ◽  
Equivalence Principle ◽  
The Other ◽  
Schwarzschild Solution ◽  
Null Geodesics ◽  
Light Rays

The fusion of two black holes — a signature phenomenon of General Relativity — is usually regarded as a process so complex that nothing short of a supercomputer simulation can accurately capture it. In this essay, we explain how the event horizon of the merger can be found in an exact analytic way in the limit where one of the black holes is much smaller than the other. Remarkably, the ideas and techniques involved are elementary: the equivalence principle, null geodesics in the Schwarzschild solution, and the notion of event horizon itself. With these, one can identify features such as the line of caustics at which light rays enter the horizon, and find indications of universal critical behavior when the two black holes touch.

scholarly journals On the double copy for spinning matter

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Yilber Fabian Bautista ◽  
Alfredo Guevara
Keyword(s):  
Black Holes ◽  
Equivalence Principle ◽  
Compact Objects ◽  
Gyromagnetic Ratio ◽  
Smooth Transition ◽  
Tree Level ◽  
Gauge Transformations ◽  
Massive Particles ◽  
Double Copy

Abstract We explore various tree-level double copy constructions for amplitudes including massive particles with spin. By working in general dimensions, we use that particles with spins s ≤ 2 are fundamental to argue that the corresponding double copy relations partially follow from compactification of their massless counterparts. This massless origin fixes the coupling of gluons, dilatons and axions to matter in a characteristic way (for instance fixing the gyromagnetic ratio), whereas the graviton couples universally reflecting the equivalence principle. For spin-1 matter we conjecture all-order Lagrangians reproducing the interactions with up to two massive lines and we test them in a classical setup, where the massive lines represent spinning compact objects such as black holes. We also test the amplitudes via CHY formulae for both bosonic and fermionic integrands. At five points, we show that by applying generalized gauge transformations one can obtain a smooth transition from quantum to classical BCJ double copy relations for radiation, thereby providing a QFT derivation for the latter. As an application, we show how the theory arising in the classical double copy of Goldberger and Ridgway can be naturally identified with a certain compactification of $$ \mathcal{N} $$ N = 4 Supergravity.

scholarly journals THERMODYNAMICS OF MODIFIED BLACK HOLES FROM GRAVITY'S RAINBOW

2007 ◽  
Vol 22 (36) ◽  
pp. 2749-2756 ◽  
Author(s):  
YI LING ◽  
XIANG LI ◽  
HONGBAO ZHANG
Keyword(s):  
Black Holes ◽  
Special Relativity ◽  
Equivalence Principle ◽  
Dispersion Relations ◽  
Specific Class ◽  
Gravity’S Rainbow ◽  
Modified Dispersion Relations ◽  
Gravity's Rainbow

We study the thermodynamics of modified black holes proposed in the context of gravity's rainbow. A notion of intrinsic temperature and entropy for these black holes is introduced. In particular for a specific class of modified Schwarzschild solutions, their temperature and entropy are obtained and compared with those previously obtained from modified dispersion relations in deformed special relativity. It turns out that the results of these two different strategies coincide, and this may be viewed as a support for the proposal of deformed equivalence principle.

scholarly journals Testing the weak-equivalence principle near black holes

2021 ◽  
Vol 104 (4) ◽  
Author(s):  
Rittick Roy ◽  
Askar B. Abdikamalov ◽  
Dimitry Ayzenberg ◽  
Cosimo Bambi ◽  
Shafqat Riaz ◽  
...  
Keyword(s):  
Black Holes ◽  
Equivalence Principle ◽  
Weak Equivalence ◽  
Weak Equivalence Principle

scholarly journals Long-Range Quantum Gravity

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1396
Author(s):  
Mariano Cadoni ◽  
Matteo Tuveri ◽  
Andrea P. Sanna
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Quantum Gravity ◽  
Long Range ◽  
Equivalence Principle ◽  
Quantum Criticality ◽  
Black Hole Thermodynamics ◽  
Gravitational Effects ◽  
Einstein's Equivalence Principle

It is a tantalising possibility that quantum gravity (QG) states remaining coherent at astrophysical, galactic and cosmological scales could exist and that they could play a crucial role in understanding macroscopic gravitational effects. We explore, using only general principles of General Relativity, quantum and statistical mechanics, the possibility of using long-range QG states to describe black holes. In particular, we discuss in a critical way the interplay between various aspects of long-range quantum gravity, such as the holographic bound, classical and quantum criticality and the recently proposed quantum thermal generalisation of Einstein’s equivalence principle. We also show how black hole thermodynamics can be easily explained in this framework.

scholarly journals Black Holes are Rejuvenating Systems of the Universe

2020 ◽  
Vol 17 ◽  
pp. 23-31
Author(s):  
Amrit Srecko Sorli
Keyword(s):  
Black Holes ◽  
Cosmic Rays ◽  
Equivalence Principle ◽  
Quantum Vacuum ◽  
Mass Energy ◽  
Physical Origin ◽  
Stellar Objects ◽  
Universal Space ◽  
Energy Equivalence ◽  
The Universe

Recent research on superfluid quantum vacuum as the physical origin of universal space has opened new perspectives in astronomy and cosmology. Every stellar object is in the active relation with space and its density diminishes according to the mass-energy equivalence principle. As per Newton’s Shell Theorem, vacuum density is minimum at the surface of the stellar objects and in their centre. The density of space on the surface of the Black holes and in their centre is so low that atoms become unstable. Therefore, they disintegrate back into the elementary particles and cosmic rays. By transforming old matter into these fresh energies, black holes are rejuvenating the universe and keeping its entropy constant.

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