scholarly journals Quantum nature of black holes: fast scrambling versus echoes

2020 ◽  
Vol 2020 (4) ◽  
Author(s):  
Krishan Saraswat ◽  
Niayesh Afshordi
Keyword(s):  
Black Holes ◽  
Quantum Nature

scholarly journals Reshaping our understanding on structure formation with the quantum nature of the dark matter

2021 ◽  
Author(s):  
C. R. Argüelles ◽  
E. A. Becerra-Vergara ◽  
A. Krut ◽  
R. Yunis ◽  
J. A. Rueda ◽  
...  
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Structure Formation ◽  
Initial Conditions ◽  
Coarse Grained ◽  
Intermediate Mass ◽  
Open Problems ◽  
Nonlinear Structure ◽  
The Core ◽  
Quantum Nature

We study the nonlinear structure formation in cosmology accounting for the quantum nature of the dark matter (DM) particles in the initial conditions at decoupling, as well as in the relaxation and stability of the DM halos. Different from cosmological N-body simulations, we use a thermodynamic approach for collisionless systems of self-gravitating fermions in general relativity, in which the halos reach the steady state by maximizing a coarse-grained entropy. We show the ability of this approach to provide answers to crucial open problems in cosmology, among others: the mass and nature of the DM particle, the formation and nature of supermassive black holes in the early Universe, the nature of the intermediate mass black holes in small halos, and the core-cusp problem.

scholarly journals Near-AdS2 Spectroscopy: Classifying the Spectrum of Operators and Interactions in N=2 4D Supergravity

Universe ◽  
2021 ◽  
Vol 7 (12) ◽  
pp. 475
Author(s):  
Alejandra Castro ◽  
Evita Verheijden
Keyword(s):  
Black Holes ◽  
Spherically Symmetric ◽  
Quantum Nature ◽  
Matter Fields ◽  
Striking Effect ◽  
Extremal Black Holes

We describe holographic properties of near-AdS2 spacetimes that arise within spherically symmetric configurations of N=2 4D U(1)4 supergravity for both gauged and ungauged theories. These theories pose a rich space of AdS2×S2 backgrounds, and their responses in the near-AdS2 region are not universal. In particular, we show that the spectrum of operators is dual to the matter fields, and their cubic interactions are sensitive to properties of the background and the theory it is embedded in. The properties that have the most striking effect are whether the background is supersymmetric or not and if the theory is gauged or ungauged. Interesting effects are due to the appearance of operators with Δ<2, which depending on the background, can lead to, for instance, instabilities or extremal correlators. The resulting differences will have an imprint on the quantum nature of the microstates of near-extremal black holes, reflecting that not all extremal black holes respond equally when kicked away from extremality.

scholarly journals ON QUANTUM NATURE OF BLACK-HOLE SPACETIME: A POSSIBLE NEW SOURCE OF INTENSE RADIATION

1999 ◽  
Vol 08 (05) ◽  
pp. 651-657 ◽  
Author(s):  
D. V. AHLUWALIA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Primary Source ◽  
Pauli Exclusion Principle ◽  
Exclusion Principle ◽  
Related Phenomenon ◽  
Quantum Nature ◽  
Black Hole Spacetime ◽  
General Relativistic ◽  
Intense Radiation

Atoms and the planets acquire their stability from the quantum mechanical incompatibility of the position and momentum measurements. This incompatibility is expressed by the fundamental commutator [x, px]=iℏ, or equivalently, via the Heisenberg's uncertainty principle Δx Δ px~ℏ. A further stability-related phenomenon where the quantum realm plays a dramatic role is the collapse of certain stars into white dwarfs and neutron stars. Here, an intervention of the Pauli exclusion principle, via the fermionic degenerate pressure, stops the gravitational collapse. However, by the neutron-star stage the standard quantum realm runs dry. One is left with the problematic collapse of a black hole. This essay is devoted to a concrete argument on why the black-hole spacetime itself should exhibit a quantum nature. The proposed quantum aspect of spacetime is shown to prevent the general-relativistic dictated problematic collapse. The quantum nature of black-hole spacetime is deciphered from a recent result on the universal equal-area spacing [Formula: see text] for black holes. In one interpretation of the emergent picture, an astrophysical black hole can fluctuate to [Formula: see text] time its classical size, and thus allow radiation and matter to escape to the outside observers. These fluctuations I conjecture provide a new source, perhaps beyond Hawking radiation, of intense radiation from astrophysical black holes and may be the primary source of observed radiation from those galactic cores what carry black hole(s). The presented interpretation may be used as a criterion to choose black holes from black hole candidates.

scholarly journals QUANTUM NATURE OF BLACK HOLES

2004 ◽  
Vol 13 (10) ◽  
pp. 2299-2305 ◽  
Author(s):  
ADAM D. HELFER
Keyword(s):  
Black Holes ◽  
Quantum Gravity ◽  
Gravitational Collapse ◽  
Dominant Role ◽  
High Energy ◽  
Ultra High Energy ◽  
Quantum Fields ◽  
Vacuum Fluctuations ◽  
High Energies ◽  
Quantum Nature

I reconsider Hawking's analysis of the effects of gravitational collapse on quantum fields, taking into account interactions between the fields. The ultra-high energy vacuum fluctuations, which had been considered to be an awkward peripheral feature of the analysis, are shown to play a key role. By interactions, they can scatter particles to, or create pairs of particle at, ultra-high energies. The energies rapidly become so great that quantum gravity must play a dominant role. Thus the vicinities of black holes are essentially quantum-gravitational regimes.

scholarly journals NONSINGULAR CHARGED BLACK HOLES À LA PALATINI

2012 ◽  
Vol 21 (08) ◽  
pp. 1250067 ◽  
Author(s):  
GONZALO J. OLMO ◽  
DIEGO RUBIERA-GARCÍA
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Mass Spectrum ◽  
Quadratic Extension ◽  
Charged Black Holes ◽  
The Core ◽  
Quantum Nature ◽  
Electrically Charged ◽  
Discreteness Condition ◽  
Nature Of Matter

We argue that the quantum nature of matter and gravity should lead to a discretization of the allowed states of the matter confined in the interior of black holes. To support and illustrate this idea, we consider a quadratic extension of general relativity (GR) formulated à la Palatini and show that nonrotating, electrically charged black holes develop a compact core at the Planck density which is nonsingular if the mass spectrum satisfies a certain discreteness condition. We also find that the area of the core is proportional to the number of charges times the Planck area.

Black holes have ring of truth

Nature ◽  
2002 ◽  
Author(s):  
Philip Ball
Keyword(s):  
Black Holes
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