scholarly journals Quantum gravity: Physics from supergeometries

2014 ◽  
Vol 11 (08) ◽  
pp. 1450067 ◽  
Author(s):  
Diego Julio Cirilo-Lombardo ◽  
Thiago Prudêncio

We show that the metric (line element) is the first geometrical object to be associated to a discrete (quantum) structure of the spacetime without necessity of black hole-entropy-area arguments, in sharp contrast with other attempts in the literature. To this end, an emergent metric solution obtained previously in [ Phys. Lett. B661 (2008) 186–191] from a particular non-degenerate Riemannian superspace is introduced. This emergent metric is described by a physical coherent state belonging to the metaplectic group Mp (n) with a Poissonian distribution at lower n (number basis) restoring the classical thermal continuum behavior at large n(n → ∞), or leading to non-classical radiation states, as is conjectured in a quite general basis by means of the Bekenstein–Mukhanov effect. Group-dependent conditions that control the behavior of the macroscopic regime spectrum (thermal or not), as the relationship with the problem of area/entropy of the black hole are presented and discussed.

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 858
Author(s):  
Dongshan He ◽  
Qingyu Cai

In this paper, we present a derivation of the black hole area entropy with the relationship between entropy and information. The curved space of a black hole allows objects to be imaged in the same way as camera lenses. The maximal information that a black hole can gain is limited by both the Compton wavelength of the object and the diameter of the black hole. When an object falls into a black hole, its information disappears due to the no-hair theorem, and the entropy of the black hole increases correspondingly. The area entropy of a black hole can thus be obtained, which indicates that the Bekenstein–Hawking entropy is information entropy rather than thermodynamic entropy. The quantum corrections of black hole entropy are also obtained according to the limit of Compton wavelength of the captured particles, which makes the mass of a black hole naturally quantized. Our work provides an information-theoretic perspective for understanding the nature of black hole entropy.


2019 ◽  
Vol 97 (12) ◽  
pp. 1317-1322
Author(s):  
Abeer Al-Modlej ◽  
Salwa Alsaleh ◽  
Hassan Alshal ◽  
Ahmed Farag Ali

Virtual black holes in noncommutative space–time are investigated using coordinate coherent state formalism such that the event horizon of a black hole is manipulated by smearing it with a Gaussian of width [Formula: see text], where θ is the noncommutativity parameter. Proton lifetime, the main associated phenomenology of the noncommutative virtual black holes, has been studied, first in four-dimensional space–time and then generalized to D dimensions. The lifetime depends on θ and the number of space–time dimensions such that it emphasizes on the measurement of proton lifetime as a potential probe for the microstructure of space–time.


2002 ◽  
Vol 17 (01) ◽  
pp. 51-58 ◽  
Author(s):  
SACHIKO OGUSHI

The relationship between the entropy of de Sitter (dS) Schwarzschild space and that of the CFT, which lives on the brane, is discussed by using Friedmann–Robertson–Walker (FRW) equations and Cardy–Verlinde formula. The cosmological constant appears on the brane with time-like metric in dS Schwarzschild background. On the other hand, in case of the brane with space-like metric in dS Schwarzschild background, the cosmological constant of the brane does not appear because we can choose brane tension to cancel it. We show that when the brane crosses the horizon of dS Schwarzschild black hole, both for time-like and space-like cases, the entropy of the CFT exactly agrees with the black hole entropy of five-dimensional dS background as it happens in the AdS/CFT correspondence.


1994 ◽  
Vol 03 (01) ◽  
pp. 317-321
Author(s):  
BERNARD F. WHITING

Brief statements are given on recent results in the following areas: 1) The derivation of a variational (maximum) principle for black hole entropy, and an outline of the physically reasonable properties of the related solution for the density of states in the microcanonical equilibrium ensemble (with Jeffrey Melmed, University of Maine). 2) Analysis of topological contributions to black hole entropy in Lovelock gravity, and the corresponding thermodynamic identity (with Jonathan Z. Simon, University of Maryland). 3) Stability analysis for a shell of matter surrounding a black hole in microcanonical (thermal) equilibrium (with Gerald Horwitz, Hebrew University, Jerusalem)—results from this work can be compared with an earlier analysis of the purely mechanical stability of the shell, and with known properties of both the dynamical and thermal stability for the black hole without a shell. 4) The study of a simple ‘singularity'-free model of gravitational collapse, and an examination of the relationship between the ensuing preservation of quantum coherence and the usual perception that mixed states should be associated with the late time emission of Hawking radiation from a classically formed black hole (with Gerard ’t Hooft and Chris Stephens, University of Utrecht).


Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 630
Author(s):  
Constantino Tsallis

In the present Reply we restrict our focus only onto the main erroneous claims by Pessoa and Costa in their recent Comment (Entropy 2020, 22, 1110).


1991 ◽  
Vol 06 (33) ◽  
pp. 3039-3045 ◽  
Author(s):  
JISHNU DEY ◽  
MIRA DEY ◽  
MARCELO SCHIFFER ◽  
LAURO TOMIO

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.


2008 ◽  
Vol 77 (6) ◽  
Author(s):  
Tatsuo Azeyanagi ◽  
Tatsuma Nishioka ◽  
Tadashi Takayanagi

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