scholarly journals State of matter at high density and entropy bounds

2015 ◽  
Vol 24 (12) ◽  
pp. 1544016 ◽  
Author(s):  
Ali Masoumi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Theory ◽  
Simple Model ◽  
Maximum Entropy ◽  
Ordinary Matter ◽  
Homogeneous Cosmology ◽  
Entropy Bound ◽  
Entropy Bounds ◽  
State Of Matter

Entropy of all systems that we understand well is proportional to their volumes except for black holes given by their horizon area. This makes the microstates of any quantum theory of gravity drastically different from the ordinary matter. Because of the assumption that black holes are the maximum entropy states, there have been many conjectures that put the area, defined one way or another, as a bound on the entropy in a given region of spacetime. Here, we construct a simple model with entropy proportional to volume which exceeds the entropy of a single black hole. We show that a homogeneous cosmology filled with this gas exceeds one of the tightest entropy bounds, the covariant entropy bound and discuss the implications.

THE BLACK HOLE ENTROPY BOUND AND THE MAXIMUM TEMPERATURE FOR MESON FORMATION IN THE NUCLEAR FIREBALL

1991 ◽  
Vol 06 (33) ◽  
pp. 3039-3045 ◽  
Author(s):  
JISHNU DEY ◽  
MIRA DEY ◽  
MARCELO SCHIFFER ◽  
LAURO TOMIO
Keyword(s):  
Black Hole ◽  
Simple Model ◽  
Black Hole Entropy ◽  
Heavy Ion ◽  
Black Hole Thermodynamics ◽  
Maximum Temperature ◽  
Ion Collisions ◽  
Pion Interferometry ◽  
Entropy Bound ◽  
Confined System

The entropy bound from black hole thermodynamics can be invoked to set limits for temperatures at which hadrons can survive as a confined system. We find that this implies that the pion can be formed in heavy ion collisions, much later than heavier mesons, for example the ρ-meson, when the fireball is cooler. The temperature found in a simple model agree qualitatively with experiment. We also suggest that this may be the reason why in pion interferometry experiments the space-time volume of the pion source seems large.

scholarly journals Black Holes and Wormholes in Extended Gravity

Universe ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 25 ◽  
Author(s):  
Stanislav Alexeyev ◽  
Maxim Sendyuk
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Quantum Theory ◽  
Gravity Models ◽  
Astrophysical Data ◽  
Effective Gravity ◽  
Extended Gravity ◽  
Theory Of Gravity ◽  
Hawking Evaporation

We discuss black hole type solutions and wormhole type ones in the effective gravity models. Such models appear during the attempts to construct the quantum theory of gravity. The mentioned solutions, being, mostly, the perturbative generalisations of well-known ones in general relativity, carry out additional set of parameters and, therefore could help, for example, in the studying of the last stages of Hawking evaporation, in extracting the possibilities for the experimental or observational search and in helping to constrain by astrophysical data.

scholarly journals BLACK HOLE UNCERTAINTIES

1993 ◽  
Vol 08 (20) ◽  
pp. 1925-1941
Author(s):  
ULF H. DANIELSSON
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Theory ◽  
Uncertainty Relation ◽  
Wave Functions ◽  
Uncertainty Relations ◽  
Two Dimensional ◽  
Black Hole Mass ◽  
Dilaton Black Holes

In this work the quantum theory of two-dimensional dilaton black holes is studied using the Wheeler-De Witt equation. The solutions correspond to wave functions of the black hole. It is found that for an observer inside the horizon, there are uncertainty relations for the black hole mass and a parameter in the metric determining the Hawking flux. Only for a particular value of this parameter can both be known with arbitrary accuracy. In the generic case there is instead a relation that is very similar to the so-called string uncertainty relation.

scholarly journals Three puzzles in cosmology

2020 ◽  
Vol 29 (14) ◽  
pp. 2030013
Author(s):  
Samir D. Mathur
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Theory ◽  
Black Hole Physics ◽  
Information Paradox ◽  
Fundamental Structure

Cosmology presents us with several puzzles that are related to the fundamental structure of quantum theory. We discuss three such puzzles, linking them to effects that arise in black hole physics. We speculate that puzzles in cosmology may be resolved by the vecro structure of the vacuum that resolves the information paradox and the “bags of gold” problem for black holes.

BLACK HOLE ENTROPY AND QUANTUM MECHANICS IN GENERIC 2-D DILATON GRAVITY

1996 ◽  
Vol 05 (06) ◽  
pp. 665-678
Author(s):  
G. KUNSTATTER
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Mechanics ◽  
Quantum Theory ◽  
Recent Work ◽  
Imaginary Part ◽  
Black Hole Entropy ◽  
Dilaton Gravity ◽  
Charged Black Holes ◽  
Classical Thermodynamics

We review some recent work concerning the classical thermodynamics and quantum mechanics of charged black holes in generic 2-D dilaton gravity. The main result that has emerged from this work is an intriguing connection between the classical black hole entropy and the imaginary part of the WKB phase of energy and charge eigenstates in the corresponding quantum theory.

Black Holes and Quantum Gravity

2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Aurélien Barrau
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Theory ◽  
Quantum Gravity ◽  
Gravitational Waves ◽  
Quantum Theory Of Gravitation ◽  
Theoretical Physics ◽  
Radio Interferometry ◽  
Theory Of Gravitation ◽  
Observational Science

The search for a quantum theory of gravitation is considered one of the most important problems in theoretical physics. Might black holes provide a key? Researchers are beginning to think that the emergence of a true black hole astronomy based on the measurement of gravitational waves and radio interferometry could bring quantum gravity into the field of experimental or observational science.

On the reality of Hawking radiation

2019 ◽  
Vol 28 (16) ◽  
pp. 2040001
Author(s):  
Asghar Qadir
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Theory ◽  
Hawking Radiation ◽  
Black Hole Thermodynamics ◽  
The Public ◽  
Roger Penrose ◽  
The Subject

Hawking radiation caught the imagination of the public and physicists alike, because it seemed so counter-intuitive. By their very definition, black holes were supposed to endlessly absorb, but never emit, matter and energy. Yet, Hawking argued that taking Quantum Theory into account, they would radiate. The further belief was that Bekenstein and Hawking had developed the field of Black Hole Thermodynamics. Here I want to correct this impression and give due credit to Roger Penrose for founding the subject. Further, I discuss the question of whether Hawking radiation should be expected to really exist, arguing that there is reason to doubt it.

scholarly journals FUNDAMENTAL SPATIO-TEMPORAL DECOHERENCE: A KEY TO SOLVING THE CONCEPTUAL PROBLEMS OF BLACK HOLES, COSMOLOGY AND QUANTUM MECHANICS

2006 ◽  
Vol 15 (12) ◽  
pp. 2181-2185 ◽  
Author(s):  
RODOLFO GAMBINI ◽  
RAFAEL A. PORTO ◽  
JORGE PULLIN
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Mechanics ◽  
Quantum Theory ◽  
Measurement Problem ◽  
Fundamental Level ◽  
Black Hole Information ◽  
Conceptual Problems ◽  
Spatio Temporal ◽  
Loss Of Coherence

Unitarity is a pillar of quantum theory. Nevertheless, it is also a source of several of its conceptual problems. We note that in a world where measurements are relational, as is the case in gravitation, quantum mechanics exhibits a fundamental level of loss of coherence. This can be the key to solving, among others, the puzzles posed by the black hole information paradox, the formation of inhomogeneities in cosmology and the measurement problem in quantum mechanics.

scholarly journals A COMMENTARY ON RUPPEINER METRICS FOR BLACK HOLES

2008 ◽  
Vol 23 (26) ◽  
pp. 2149-2161 ◽  
Author(s):  
A. J. M. MEDVED
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Simple Model ◽  
Btz Black Hole

There has been some recent controversy regarding the Ruppeiner metrics that are induced by Reissner–Nordström (and Reissner–Nordström-like) black holes. Most infamously, why does this family of metrics turn out to be flat, how is this outcome to be physically understood, and can/should the formalism be suitably modified to induce curvature? In this paper, we provide a novel interpretation of this debate. For the sake of maximal analytic clarity and tractability, some supporting calculations are carried out for the relatively simple model of a rotating BTZ black hole.

Towards exterior/interior correspondence of black-holes

2020 ◽  
Vol 17 (12) ◽  
pp. 2050180
Author(s):  
C. Avilés-Niebla ◽  
P. A. Nieto-Marín ◽  
J. A. Nieto
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Complex Plane ◽  
Spiral Galaxies ◽  
Simple Approach ◽  
Dimensional Sphere ◽  
Light Velocity ◽  
Ordinary Matter ◽  
Schwarzschild Radius ◽  
Faster Than Light

We describe a simple approach for a possible connection between the exterior and interior of black-holes. According to our result, the Schwarzschild radius determines a [Formula: see text]-dimensional sphere that separates two worlds: the exterior, where ordinary matter moves with velocities less than the light velocity, and the interior, where tachyons move with velocities greater than the light velocity. Moreover, we find a geometric map in the complex plane that connects ordinary matter with faster than light particles. Motivated by these results, we also find that the exterior and the interior structures of black-holes can be unified in a world of [Formula: see text]-dimensions. Finally, we comment about the possibility that superluminal particles in the interior of a black-hole may provide an alternative solution of the rotation curves of spiral galaxies.

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