scholarly journals Semiclassical $$ \mathcal{S} $$-matrix and black hole entropy in dilaton gravity

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Maxim Fitkevich ◽  
Dmitry Levkov ◽  
Sergey Sibiryakov
Keyword(s):  
Black Hole ◽  
Scattering Amplitude ◽  
Black Hole Entropy ◽  
Point Particle ◽  
Dilaton Gravity ◽  
Black Hole Mass ◽  
Final State ◽  
S Matrix ◽  
Semiclassical Solution ◽  
Unit Probability

Abstract We use complex semiclassical method to compute scattering amplitudes of a point particle in dilaton gravity with a boundary. This model has nonzero minimal black hole mass Mcr. We find that at energies below Mcr the particle trivially scatters off the boundary with unit probability. At higher energies the scattering amplitude is exponentially suppressed. The corresponding semiclassical solution is interpreted as formation of an intermediate black hole decaying into the final-state particle. Relating the suppression of the scattering probability to the number of the intermediate black hole states, we find an expression for the black hole entropy consistent with thermodynamics. In addition, we fix the constant part of the entropy which is left free by the thermodynamic arguments. We rederive this result by modifying the standard Euclidean entropy calculation.

scholarly journals Does the HM mechanism work in string theory?

2013 ◽  
Vol 91 (1) ◽  
pp. 75-80
Author(s):  
Alireza Sepehri ◽  
Somayyeh Shoorvazi ◽  
Mohammad Ebrahim Zomorrodian
Keyword(s):  
Hilbert Space ◽  
Black Hole ◽  
String Theory ◽  
Correspondence Principle ◽  
Black Hole Entropy ◽  
Closed String ◽  
Centre Of Mass ◽  
Final State ◽  
Information Transformation ◽  
Left And Right

The correspondence principle offers a unique opportunity to test the Horowitz and Maldacena mechanism at the correspondence point “the centre of mass energies around (Ms/(gs)2)”. First by using the Horowitz and Maldacena proposal, the black hole final state for closed strings is studied and the entropy of these states is calculated. Then, to consider the closed string states, a copy of the original Hilbert space is constructed with a set of creation–annihilation operators that have the same commutation properties as the original ones. The total Hilbert space is the tensor product of the two spaces Hright ⊗ Hleft, where in this case Hleft/right denote the physical quantum state space of the closed string. It is shown that closed string states can be represented by a maximally entangled two-mode squeezed state of the left and right spaces of closed string. Also, the entropy for these string states is calculated. It is found that black hole entropy matches the closed string entropy at transition point. This means that our result is consistent with correspondence principle and thus HM mechanism in string theory works. Consequently the unitarity of the black hole in string theory can be reconciled. However Gottesman and Preskill point out that, in this scenario, departures from unitarity can arise due to interactions between the collapsing body and the infalling Hawking radiation inside the event horizon and information can be lost. By extending the Gottesman and Preskill method to string theory, the amount of information transformation from the matter to the state of outgoing Hagedorn radiation for closed strings is obtained. It is observed that information is lost for closed strings.

scholarly journals THE VIRTUAL BLACK HOLE IN 2D QUANTUM GRAVITY AND ITS RELEVANCE FOR THE S-MATRIX

2002 ◽  
Vol 17 (06n07) ◽  
pp. 989-992 ◽  
Author(s):  
DANIEL GRUMILLER
Keyword(s):  
Black Hole ◽  
Quantum Gravity ◽  
Wave Scattering ◽  
Black Hole Mass ◽  
Hole Formation ◽  
S Wave ◽  
Scalar Matter ◽  
S Matrix ◽  
Tree Vertex ◽  
Classical Mechanism

As shown recently 2d quantum gravity theories — including spherically reduced Einstein-gravity — after an exact path integral of its geometric part can be treated perturbatively in the loops of (scalar) matter. Obviously the classical mechanism of black hole formation should be contained in the tree approximation of the theory. This is shown to be the case for the scattering of two scalars through an intermediate state which by its effective black hole mass is identified as a "virtual black hole". We discuss the lowest order tree vertex for minimally and non-minimally coupled scalars and find a non-trivial finite S-matrix for gravitational s-wave scattering in the latter case.

scholarly journals A CONFORMAL AFFINE TODA MODEL OF 2D BLACK HOLES: A QUANTUM STUDY OF THE EVAPORATION END POINT

1993 ◽  
Vol 08 (27) ◽  
pp. 2593-2605
Author(s):  
F. BELGIORNO ◽  
A.S. CATTANEO ◽  
F. FUCITO ◽  
M. MARTELLINI
Keyword(s):  
Field Theory ◽  
Black Holes ◽  
Black Hole ◽  
Group Analysis ◽  
Black Hole Thermodynamics ◽  
Dilaton Gravity ◽  
Final State ◽  
Renormalization Group Analysis ◽  
Conformal Field ◽  
Toda Model

In this paper we reformulate the dilaton-gravity theory of Callan et al. as a new effective conformal field theory which turns out to be a generalization of the so-called SL 2-conformal affine Toda (CAT) theory studied some time ago by Babelon and Bonora. We quantize this model, thus keeping in account the dilaton-gravity quantum effects. We then implement a Renormalization Group analysis to study the black hole thermodynamics and the final state of the Hawking evaporation.

scholarly journals Conformal bootstrap in dS/CFT and topological quantum gravity

2019 ◽  
Vol 17 (01) ◽  
pp. 2050007
Author(s):  
Andrea Addazi ◽  
Antonino Marcianò
Keyword(s):  
Black Hole ◽  
Quantum Gravity ◽  
Scattering Amplitude ◽  
Black Hole Entropy ◽  
Gravitational Instantons ◽  
Conformal Bootstrap ◽  
Topological Quantum ◽  
Black Hole Information ◽  
Kitaev Model ◽  
Spin Representations

We show that the correspondence among [Formula: see text], the 1D Schwarzian Model, Sachdev–Ye–Kitaev model and [Formula: see text] Topological Quantum Gravity can be extended to the case of [Formula: see text]. The [Formula: see text]-matrix, related to the gravitational scattering amplitude near the horizon of [Formula: see text] black hole, corresponds (on the side of the holographic projection) to a crossing kernel in the Schwarzian Model. The [Formula: see text]-matrix is related to the 6j-symbol of SU[Formula: see text]. We also find that in the Euclidean [Formula: see text] a new Kac–Moody symmetry of instantons emerges out. We dub these new solutions Kac–Moodions. A one-to-one correspondence of Kac–Moodion levels and SU[Formula: see text] spin representations is established. Every instanton then corresponds to spin representations deployed in Topological Quantum Gravity. The instantons are directly connected to the Black Hole entropy as punctures on its horizon. This strongly supports the recent proposal, in arXiv:1707.00347, that a Kac–Moody symmetry of gravitational instantons is related to the black hole information processing. We also comment on a further correspondence that can be established between the Schwarzian Model and noncommutative spacetimes in [Formula: see text]D, passing through the equivalence with Topological Quantum Gravity with cosmological constant, in the limit when the latter vanishes.

scholarly journals TOWARDS A THEORY OF QUANTUM BLACK HOLES

2002 ◽  
Vol 17 (06n07) ◽  
pp. 979-988 ◽  
Author(s):  
VICTOR BEREZIN
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Mass Spectrum ◽  
Gravitational Collapse ◽  
Black Hole Entropy ◽  
Black Hole Mass ◽  
Quantum Black Hole ◽  
Classical Analog ◽  
Hole Model ◽  
Specific Quantum

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.

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.

scholarly journals BLACK HOLE AS AN INFORMATION ERASER

2010 ◽  
Vol 25 (19) ◽  
pp. 1581-1594 ◽  
Author(s):  
HYEONG-CHAN KIM ◽  
JAE-WEON LEE ◽  
JUNGJAI LEE
Keyword(s):  
Black Hole ◽  
Mass Spectra ◽  
Black Hole Entropy ◽  
Black Hole Thermodynamics ◽  
Black Hole Mass ◽  
Schwarzschild Black Hole ◽  
Efficient Information ◽  
Landauer’S Principle ◽  
Discrete Mass

We discuss the identity of black hole entropy and show that the first law of black hole thermodynamics, in the case of a Schwarzschild black hole, can be derived from Landauer's principle by assuming that the black hole is one of the most efficient information erasers. The term "most efficient" implies that maximal information will be erased for a given amount of work. We calculate the discrete mass spectra and the entropy of a Schwarzschild black hole assuming that the black hole processes information in unit of bits. The black hole entropy acquires a subleading contribution proportional to the logarithm of its mass-squared in addition to the usual mass-squared term without an artificial cutoff. We also argue that the minimum of the black hole mass is [Formula: see text]

scholarly journals Empty black holes, firewalls, and the origin of Bekenstein–Hawking entropy

2014 ◽  
Vol 23 (13) ◽  
pp. 1443007 ◽  
Author(s):  
Mehdi Saravani ◽  
Niayesh Afshordi ◽  
Robert B. Mann
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Degrees Of Freedom ◽  
Black Hole Entropy ◽  
Event Horizons ◽  
Thermodynamic Entropy ◽  
Singular Event ◽  
Physical Boundary ◽  
Semiclassical Solution

We propose a novel solution for the endpoint of gravitational collapse, in which spacetime ends (and is orbifolded) at a microscopic distance from black hole event horizons. This model is motivated by the emergence of singular event horizons in the gravitational aether theory, a semiclassical solution to the cosmological constant problem(s) and thus suggests a catastrophic breakdown of general relativity close to black hole event horizons. A similar picture emerges in fuzzball models of black holes in string theory, as well as the recent firewall proposal to resolve the information paradox. We then demonstrate that positing a surface fluid in thermal equilibrium with Hawking radiation, with vanishing energy density (but nonvanishing pressure) at the new boundary of spacetime, which is required by Israel junction conditions, yields a thermodynamic entropy that is identical to the Bekenstein–Hawking area law, SBH, for charged rotating black holes. To our knowledge, this is the first derivation of black hole entropy that only employs local thermodynamics. Furthermore, a model for the microscopic degrees of freedom of the surface fluid (which constitute the microstates of the black hole) is suggested, which has a finite, but Lorentz-violating, quantum field theory. Finally, we comment on the effects of physical boundary on Hawking radiation and show that relaxing the assumption of equilibrium with Hawking radiation sets SBH as an upper limit for Black Hole entropy.

scholarly journals X-Ray Determination of the Black-Hole Mass in Cygnus X-1

1998 ◽  
Vol 188 ◽  
pp. 388-389
Author(s):  
A. Kubota ◽  
K. Makishima ◽  
T. Dotani ◽  
H. Inoue ◽  
K. Mitsuda ◽  
...  
Keyword(s):  
Black Hole ◽  
Compact Object ◽  
Optical Observations ◽  
Black Hole Mass ◽  
X Ray ◽  
Upper Limit ◽  
Supergiant Star ◽  
X Ray Binaries ◽  
Two Bodies

About 10 X-ray binaries in our Galaxy and LMC/SMC are considered to contain black hole candidates (BHCs). Among these objects, Cyg X-1 was identified as the first BHC, and it has led BHCs for more than 25 years(Oda 1977, Liang and Nolan 1984). It is a binary system composed of normal blue supergiant star and the X-ray emitting compact object. The orbital kinematics derived from optical observations indicates that the compact object is heavier than ~ 4.8 M⊙ (Herrero 1995), which well exceeds the upper limit mass for a neutron star(Kalogora 1996), where we assume the system consists of only two bodies. This has been the basis for BHC of Cyg X-1.

scholarly journals Wandering of the central black hole in a galactic nucleus and correlation of the black hole mass with the bulge mass

2021 ◽  
Author(s):  
Hajime Inoue
Keyword(s):  
Black Hole ◽  
Loss Rate ◽  
Energy Gain ◽  
Stellar Disk ◽  
Black Hole Mass ◽  
Central Black Hole ◽  
Massive Black Hole ◽  
Stellar Cluster ◽  
Upper Limit ◽  
Simple Parameter

Abstract We investigate a mechanism for a super-massive black hole at the center of a galaxy to wander in the nucleus region. A situation is supposed in which the central black hole tends to move by the gravitational attractions from the nearby molecular clouds in a nuclear bulge but is braked via the dynamical frictions from the ambient stars there. We estimate the approximate kinetic energy of the black hole in an equilibrium between the energy gain rate through the gravitational attractions and the energy loss rate through the dynamical frictions in a nuclear bulge composed of a nuclear stellar disk and a nuclear stellar cluster as observed from our Galaxy. The wandering distance of the black hole in the gravitational potential of the nuclear bulge is evaluated to get as large as several 10 pc, when the black hole mass is relatively small. The distance, however, shrinks as the black hole mass increases, and the equilibrium solution between the energy gain and loss disappears when the black hole mass exceeds an upper limit. As a result, we can expect the following scenario for the evolution of the black hole mass: When the black hole mass is smaller than the upper limit, mass accretion of the interstellar matter in the circumnuclear region, causing the AGN activities, makes the black hole mass larger. However, when the mass gets to the upper limit, the black hole loses the balancing force against the dynamical friction and starts spiraling downward to the gravity center. From simple parameter scaling, the upper mass limit of the black hole is found to be proportional to the bulge mass, and this could explain the observed correlation of the black hole mass with the bulge mass.

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