scholarly journals MICROCANONICAL MODEL FOR A GAS OF EVAPORATING BLACK HOLES AND STRINGS, SCATTERING AMPLITUDES AND MASS SPECTRUM

2008 ◽  
Vol 23 (07) ◽  
pp. 975-1000 ◽  
Author(s):  
D. J. CIRILO-LOMBARDO ◽  
N. G. SANCHEZ

We study the system formed by a gas of black holes and strings within a microcanonical formulation. The density of mass levels grows asymptotically as [Formula: see text], (i = 1,…,N). We derive the microcanonical content of the system: entropy, equation of state, number of components N, temperature T and specific heat. The pressure and the specific heat are negative reflecting the gravitational unstability and a nonhomogeneous configuration. The asymptotic behavior of the temperature for large masses emerges as the Hawking temperature of the system (classical or semiclassical phase) in which the classical black hole behavior dominates, while for small masses (quantum black hole or string behavior) the temperature becomes the string temperature which emerges as the critical temperature of the system. At low masses, a phase transition takes place showing the passage from the classical (black hole) to quantum (string) behavior. Within a microcanonical field theory formulation, the propagator describing the string–particle–black hole system is derived and from it the interacting four-point scattering amplitude of the system is obtained. For high masses it behaves asymptotically as the degeneracy of states ρ(m) of the system (i.e. duality or crossing symmetry). The microcanonical propagator and partition function are derived from a (Nambu–Goto) formulation of the N-extended objects and the mass spectrum of the black hole–string system is obtained: for small masses (quantum behavior) these yield the usual pure string scattering amplitude and string–particle spectrum [Formula: see text]; for growing mass the spectrum describes all the intermediate states up to the pure black hole behavior. The different black hole behaviors according to the different mass ranges: classical, semiclassical and quantum or string behaviors are present in the model.

2002 ◽  
Vol 17 (06n07) ◽  
pp. 979-988 ◽  
Author(s):  
VICTOR BEREZIN

We describe some specific quantum black hole model. It is pointed out that the origin of a black hole entropy is the very process of quantum gravitational collapse. The quantum black hole mass spectrum is extracted from the mass spectrum of the gravitating source. The classical analog of quantum black hole is constructed.


2005 ◽  
Vol 20 (13) ◽  
pp. 2813-2820 ◽  
Author(s):  
AXEL KRAUSE

We study some consequences of a recently proposed description for a Schwarzschild black hole based on Euclidean [Formula: see text] brane pairs described in terms of chain-like excitations. A discrete mass-spectrum of Bekenstein-type is inferred and upon identification of the black hole mass with the chain's energy the leading corrections to both Hawking-temperature and specific heat of the black hole are obtained. The results indicate that for small black holes the evaporation process might be considerably altered.


Physics ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 372-378
Author(s):  
Viktor D. Stasenko ◽  
Alexander A. Kirillov

In this paper, the merger rate of black holes in a cluster of primordial black holes (PBHs) is investigated. The clusters have characteristics close to those of typical globular star clusters. A cluster that has a wide mass spectrum ranging from 10−2 to 10M⊙ (Solar mass) and contains a massive central black hole of the mass M•=103M⊙ is considered. It is shown that in the process of the evolution of cluster, the merger rate changed significantly, and by now, the PBH clusters have passed the stage of active merging of the black holes inside them.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Chang Liu ◽  
Yan-Gang Miao ◽  
Yu-Mei Wu ◽  
Yu-Hao Zhang

We suggest a quantum black hole model that is based on an analogue to hydrogen atoms. A self-regular Schwarzschild-AdS black hole is investigated, where the mass density of the extreme black hole is given by the probability density of the ground state of hydrogen atoms and the mass densities of nonextreme black holes are given by the probability densities of excited states with no angular momenta. Such an analogue is inclined to adopt quantization of black hole horizons. In this way, the total mass of black holes is quantized. Furthermore, the quantum hoop conjecture and the Correspondence Principle are discussed.


2020 ◽  
Vol 35 (10) ◽  
pp. 2050070
Author(s):  
Ujjal Debnath

We study the four-dimensional (i) modified Bardeen black hole, (ii) modified Hayward black hole, (iii) charged regular black hole and (iv) magnetically charged regular black hole. For modified Bardeen black hole and modified Hayward black hole, we found only one horizon (event horizon) and then we found some thermodynamic quantities like the entropy, surface area, irreducible mass, temperature, Komar energy and specific heat capacity on the event horizon. We here study the bounds of the above thermodynamic quantities for these black holes on the event horizon. Then, we examine the thermodynamics stability of the black holes with some conditions. Next, we studied the charged regular black hole and magnetically charged regular black hole and found two horizons (Cauchy and event horizons) of these black holes. Then, we found the entropy, surface area, irreducible mass, temperature, Komar energy and specific heat capacity on the Cauchy and event horizons. Then, we get some conditions for thermodynamic stability/instability of the black holes. We found the radius of the extremal horizon and Christodoulou–Ruffiini mass and then analyze the above thermodynamic quantities on the extremal horizon. We calculate the sum/subtraction, product, division and sum/subtraction of inverse of surface areas, entropies, irreducible masses, temperatures, Komar energies and specific heat capacities on both the horizons. From these, we found the bounds of the above quantities on the horizons.


2006 ◽  
Vol 2 (S238) ◽  
pp. 3-12 ◽  
Author(s):  
Jorge Casares

AbstractRadial velocity studies of X-ray binaries provide the most solid evidence for the existence of stellar-mass black holes. We currently have 20 confirmed cases, with dynamical masses in excess of 3 M⊙. Accurate masses have been obtained for a subset of systems which gives us a hint at the mass spectrum of the black hole population. This review summarizes the history of black hole discoveries and presents the latest results in the field.


2008 ◽  
Vol 23 (35) ◽  
pp. 2987-2996 ◽  
Author(s):  
ARUNAVA ROY ◽  
MARCO CAVAGLIÀ

Supersymmetry and extra dimensions are the two most promising candidates for new physics at the TeV scale. Supersymmetric particles or extra-dimensional effects could soon be observed at the Large Hadron Collider. We propose a simple but effective method to discriminate the two models: the analysis of isolated leptons with high transverse momentum. Black hole events are simulated with the CATFISH black hole generator. Supersymmetry simulations use a combination of PYTHIA and ISAJET, the latter providing the mass spectrum. Our results show that the measure of the dilepton invariant mass provides a promising signature to differentiate supersymmetry and black hole events at the Large Hadron Collider. Analysis of event-shape variables and multilepton events complement and strengthen this conclusion.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
A. V. Grobov ◽  
S. G. Rubin ◽  
V. Yu. Shalamova

A mechanism of primordial black hole formation with specific mass spectrum is discussed. It is shown that these black holes could contribute to the energy density of dark matter. Our approach is elaborated in the framework of universal extra dimensions.


2013 ◽  
Vol 22 (05) ◽  
pp. 1350022 ◽  
Author(s):  
D. DWIVEDEE ◽  
B. NAYAK ◽  
L. P. SINGH

We investigate the evolution of primordial black hole mass spectrum by including both accretion of radiation and Hawking evaporation within Brans–Dicke (BD) cosmology in radiation-, matter- and vacuum-dominated eras. We also consider the effect of evaporation of primordial black holes on the expansion dynamics of the universe. The analytic solutions describing the energy density of the black holes in equilibrium with radiation are presented. We demonstrate that these solutions act as attractors for the system ensuring stability for both linear and nonlinear situations. We show, however, that inclusion of accretion of radiation delays the onset of this equilibrium in all radiation-, matter- and vacuum-dominated eras.


2021 ◽  
Vol 2021 (12) ◽  
pp. 047
Author(s):  
Felipe F. Freitas ◽  
Carlos A.R. Herdeiro ◽  
António P. Morais ◽  
António Onofre ◽  
Roman Pasechnik ◽  
...  

Abstract We construct families, and concrete examples, of simple extensions of the Standard Model that can yield ultralight real or complex vectors or scalars with potential astrophysical relevance. Specifically, the mass range for these putative fundamental bosons (∼ 10-10-10-20 eV) would lead dynamically to both new non-black hole compact objects (bosonic stars) and new non-Kerr black holes, with masses of ∼ M⊙ to ∼ 1010 M⊙, corresponding to the mass range of astrophysical black hole candidates (from stellar mass to supermassive). For each model, we study the properties of the mass spectrum and interactions after spontaneous symmetry breaking, discuss its theoretical viability and caveats, as well as some of its potential and most relevant phenomenological implications linking them to the physics of compact objects.


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