scholarly journals On the Black-Hole Kink

1997 ◽  
Vol 06 (01) ◽  
pp. 57-68 ◽  
Author(s):  
Pedro F. González-Díaz
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Conservation Laws ◽  
Schwarzschild Black Hole ◽  
Interior Surface ◽  
Quantum Regime ◽  
Probability Of Occurrence

By allowing the light cones to tip over on hypersurfaces according to the conservation laws of an one-kink in static, Schwarzschild black-hole metric, we show that in the quantum regime there also exist instantons whose finite imaginary action gives the probability of occurrence of the kink metric corresponding to single chargeless, nonrotating black holes taking place in pairs, the holes of each pair being joined on an interior surface, beyond the horizon.

scholarly journals WHAT IS THE TOPOLOGY OF A SCHWARZSCHILD BLACK HOLE?

2012 ◽  
Vol 18 ◽  
pp. 125-129 ◽  
Author(s):  
EDMUNDO M. MONTE
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Space Time ◽  
Higher Dimension ◽  
Schwarzschild Black Hole

We investigate the topology of Schwarzschild's black holes through the immersion of this space-time in space of higher dimension. Through the immersions of Kasner and Fronsdal we calculate the extension of the Schwarzschilds black hole.

scholarly journals Shadow cast of noncommutative black holes in Rastall gravity

2020 ◽  
Vol 35 (20) ◽  
pp. 2050163 ◽  
Author(s):  
Ali Övgün ◽  
İzzet Sakallı ◽  
Joel Saavedra ◽  
Carlos Leiva
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Emission Rate ◽  
Model Parameters ◽  
Spherically Symmetric ◽  
Image Model ◽  
Schwarzschild Black Hole ◽  
Physical Validity ◽  
Shadow Cast ◽  
Noncommutative Parameter

We study the shadow and energy emission rate of a spherically symmetric noncommutative black hole in Rastall gravity. Depending on the model parameters, the noncommutative black hole can reduce to the Schwarzschild black hole. Since the nonvanishing noncommutative parameter affects the formation of event horizon, the visibility of the resulting shadow depends on the noncommutative parameter in Rastall gravity. The obtained sectional shadows respect the unstable circular orbit condition, which is crucial for physical validity of the black hole image model.

scholarly journals HAMILTONIAN FORMALISM FOR BLACK HOLES AND QUANTIZATION II

1996 ◽  
Vol 05 (03) ◽  
pp. 227-250 ◽  
Author(s):  
MARCO CAVAGLIÀ ◽  
VITTORIO DE ALFARO ◽  
ALEXANDRE T. FILIPPOV
Keyword(s):  
Hilbert Space ◽  
Black Holes ◽  
Black Hole ◽  
Invariant Measure ◽  
Hamiltonian Formalism ◽  
Quantization Method ◽  
Schwarzschild Black Hole ◽  
Canonical Formulation ◽  
Gauge Fixing ◽  
Rigid Transformations

We quantize by the Dirac-Wheeler-DeWitt method the canonical formulation of the Schwarzschild black hole developed in a previous paper. We investigate the properties of the operators that generate rigid symmetries of the Hamiltonian, establish the form of the invariant measure under the rigid transformations, and determine the gauge fixed Hilbert space of states. We also prove that the reduced quantization method leads to the same Hilbert space for a suitable gauge fixing.

scholarly journals VOROS PRODUCT AND NONCOMMUTATIVE INSPIRED BLACK HOLES

2013 ◽  
Vol 28 (09) ◽  
pp. 1350030
Author(s):  
SUNANDAN GANGOPADHYAY
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Extremal Point ◽  
De Sitter ◽  
Schwarzschild Black Hole ◽  
Standard Identity ◽  
Schwarzschild Geometry ◽  
Area Law

We emphasize the importance of the Voros product in defining the noncommutative (NC) inspired black holes. The computation of entropy for both the noncommutative inspired Schwarzschild and Reissner–Nordström (RN) black holes show that the area law holds up to order [Formula: see text]. The leading correction to the entropy (computed in the tunneling formalism) is shown to be logarithmic. The Komar energy E for these black holes is then obtained and a deviation from the standard identity E = 2STH is found at the order [Formula: see text]. This deviation leads to a nonvanishing Komar energy at the extremal point TH = 0 of these black holes. The Smarr formula is finally worked out for the NC Schwarzschild black hole. Similar features also exist for a de Sitter–Schwarzschild geometry.

scholarly journals Black hole thermodynamics in Snyder phase space

2017 ◽  
Vol 14 (11) ◽  
pp. 1750164
Author(s):  
Sara Saghafi ◽  
Kourosh Nozari
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Phase Space ◽  
Symplectic Structure ◽  
Symplectic Manifolds ◽  
Black Hole Thermodynamics ◽  
Schwarzschild Black Hole ◽  
Noncommutative Phase Space ◽  
Physics Of Black Holes ◽  
First Time

By defining a noncommutative symplectic structure, we study thermodynamics of Schwarzschild black hole in a Snyder noncommutative phase space for the first time. Since natural cutoffs are the results of compactness of symplectic manifolds in phase space, the physics of black holes in such a space would be affected mainly by these cutoffs. In this respect, this study provides a basis for more deeper understanding of the black hole thermodynamics in a pure mathematical viewpoint.

scholarly journals Photon Spheres, ISCOs, and OSCOs: Astrophysical Observables for Regular Black Holes with Asymptotically Minkowski Cores

Universe ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 2
Author(s):  
Thomas Berry ◽  
Alex Simpson ◽  
Matt Visser
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Circular Orbit ◽  
Schwarzschild Black Hole ◽  
Circular Orbits ◽  
Regular Black Hole ◽  
Astrophysical Interest ◽  
Regular Black Holes ◽  
Recent Advances ◽  
Classical Black Holes

Classical black holes contain a singularity at their core. This has prompted various researchers to propose a multitude of modified spacetimes that mimic the physically observable characteristics of classical black holes as best as possible, but that crucially do not contain singularities at their cores. Due to recent advances in near-horizon astronomy, the ability to observationally distinguish between a classical black hole and a potential black hole mimicker is becoming increasingly feasible. Herein, we calculate some physically observable quantities for a recently proposed regular black hole with an asymptotically Minkowski core—the radius of the photon sphere and the extremal stable timelike circular orbit (ESCO). The manner in which the photon sphere and ESCO relate to the presence (or absence) of horizons is much more complex than for the Schwarzschild black hole. We find situations in which photon spheres can approach arbitrarily close to (near extremal) horizons, situations in which some photon spheres become stable, and situations in which the locations of both photon spheres and ESCOs become multi-valued, with both ISCOs (innermost stable circular orbits) and OSCOs (outermost stable circular orbits). This provides an extremely rich phenomenology of potential astrophysical interest.

scholarly journals Thermodynamic metric of deformed Schwarzschild black holes

2017 ◽  
Vol 26 (10) ◽  
pp. 1750106 ◽  
Author(s):  
Wen-Yu Wen
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Ricci Scalar ◽  
Renyi Entropy ◽  
Schwarzschild Black Hole ◽  
Additional Degree ◽  
Regular Black Holes ◽  
Gauge Fixing

Thermodynamic metric usually works only for those black holes with more than one conserved charge, thereby excluding the Schwarzschild black hole. In this paper, however, different versions of thermodynamic metric are computed and compared for the Schwarzschild-like black hole by introducing new degrees of freedom. These new degrees of freedom have two purposes. First, the deformed metric may be treated offshell to the ordinary Schwarzschild black hole, and onshell physics corresponds to the submanifold by gauge fixing of this additional degree of freedom. In particular, the thermal Ricci scalar for the Schwarzschild black hole, though different for various deformations, can be obtained by switching off the deformation. Second, while deformed metric is treated onshell, a divergent Ricci scalar may signal an exotic phase in which new physical degrees of freedom manifest. This paper considers the new degree of freedom as the running Newton constant, a cutoff scale for regular black holes, a noncommutative deformation or the deformed parameter in the nonextensive Tsallis–Rènyi entropy.

scholarly journals Observing shadow of the Schwarzschild black hole in presence of a plasma

2016 ◽  
Vol 12 (S324) ◽  
pp. 351-352 ◽  
Author(s):  
Farruh Atamurotov
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Electromagnetic Radiation ◽  
Power Law ◽  
Density Profile ◽  
Particle Motion ◽  
Spherically Symmetric ◽  
Schwarzschild Black Hole ◽  
Plasma Environment ◽  
Symmetric Black Hole

AbstractWe have investigated particle motion around Schwarzschild black holes in the presence of a plasma with radial power-law density profile has been shown that the photon sphere around a spherically symmetric black hole is unchanged under the influence of the plasma; however, the Schwarzschild black hole shadow size is reduced due to the refraction of electromagnetic radiation in the plasma environment of the black hole.

scholarly journals Transonic structure of slowly rotating accretion flows with shocks around black holes

2016 ◽  
Vol 12 (S324) ◽  
pp. 23-26
Author(s):  
Petra Suková ◽  
Szymon Charzyński ◽  
Agnieszka Janiuk
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Time Scale ◽  
Mass Scale ◽  
Schwarzschild Black Hole ◽  
Transonic Flows ◽  
Accretion Flows ◽  
2D Structure ◽  
Sgr A

AbstractWe present recent results of the studies of low angular momentum accretion of matter onto Schwarzschild black hole using fully relativistic numerical simulations. We compare the resulting 2D structure of transonic flows with results of 1D pseudo-Newtonian computations of non-magnetized flow. The research has observable consequences on black holes on the whole mass scale, in particular it is related to the time-scale and shape of luminosity flares in Sgr A* or to the evolution of QPO frequency during outbursts of microquasars.

scholarly journals The Symmetry of the Interior and Exterior of Schwarzschild and Reissner–Nordstrom Black Holes—Sphere vs. Cylinder

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 859
Author(s):  
Andy T. Augousti ◽  
Andrzej Radosz ◽  
Pawel Gusin ◽  
Aleksander Kaczmarek
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dynamic Properties ◽  
Thought Experiments ◽  
Singular Behavior ◽  
Schwarzschild Black Hole ◽  
Test Particles ◽  
Anisotropic Cosmology ◽  
The Relationship ◽  
Cylindrical Axis

One can question the relationship between the symmetries of the exterior and interior of black holes with an isotropic and static exterior. This question is justified by the variety of recent findings indicating substantial or even dramatic differences in the properties of the exterior and interior of isotropic, static black holes. By invoking some of these findings related to a variety of the thought experiments with freely falling or uniformly accelerated test particles, one can establish the dynamic properties of the interior, which turn out to be equivalent to anisotropic cosmology, simultaneously expanding and contracting, albeit in different directions. In order to illustrate the comparison between the symmetry of the exterior vs. the interior, we apply conventional t, r, θ, φ coordinates to both of these ranges, although on the horizon(s) they display singular behavior. Using a simple approach based on co-moving and freely falling observers, the dynamics of the cylindrically shaped interior are explored. That enables us to present schematic snapshots of the interior of a Schwarzschild black hole, expanding along its cylindrical axis and contracting along its spherical base, as well as the interior of a Reissner–Nordström black hole, expanding first and then contracting along the cylindrical axis up to the terminal instant r =r−.

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