scholarly journals EXACT SOLUTIONS AND THE ATTRACTOR MECHANISM IN NON-BPS BLACK HOLES

2008 ◽  
Vol 23 (14n15) ◽  
pp. 2178-2180
Author(s):  
KYOSUKE HOTTA

We analyze the attractor mechanism for the D0-D4 black hole solution in the four-dimensional [Formula: see text] supergravity. Our analyses are based on new exact solutions, which show explicitly the attractor mechanism for the extremal non-BPS black holes. Our solutions take into account the moduli as general complex fields, while in almost all the non-BPS solutions obtained by previous authors, the moduli fields are restricted to be purely imaginary.

2019 ◽  
Vol 34 (35) ◽  
pp. 1930017 ◽  
Author(s):  
Antonio Gallerati

We perform a detailed analysis of black hole solutions in supergravity models. After a general introduction on black holes in general relativity and supersymmetric theories, we provide a detailed description of ungauged extended supergravities and their dualities. Therefore, we analyze the general form of black hole configurations for these models, their near-horizon behavior and characteristic of the solution. An explicit construction of a black hole solution with its physical implications is given for the STU-model. The second part of this review is dedicated to gauged supergravity theories. We describe a step-by-step gauging procedure involving the embedding tensor formalism to be used to obtain a gauged model starting from an ungauged one. Finally, we analyze general black hole solutions in gauged models, providing an explicit example for the [Formula: see text], [Formula: see text] case. A brief review on special geometry is also provided, with explicit results and relations for supersymmetric black hole solutions.


1996 ◽  
Vol 05 (06) ◽  
pp. 707-721 ◽  
Author(s):  
I. YA. AREF’EVA ◽  
I.V. VOLOVICH ◽  
K.S. VISWANATHAN

In a series of papers Amati, Ciafaloni and Veneziano and ’t Hooft conjectured that black holes occur in the collision of two light particles at planckian energies. In this talk based on [10] we discuss a possible scenario for such a process by using the Chandrasekhar-Ferrari-Xanthopoulos duality between the Kerr black hole solution and colliding plane gravitational waves.


Author(s):  
Sergey Kruglov

An exact spherically symmetric and magnetically charged black hole solution in 4D Einstein-Gauss-Bonnet gravity coupled to nonlinear electrodynamics (NED) is obtained. The NED Lagrangian is given by ${\cal L}_{NED} = -{\cal F}/(1+\sqrt[4]{2\beta{\cal F}})$, where ${\cal F}$ is the field invariant. We study the thermodynamics calculating the Hawking temperature and the heat capacity of the black hole. The phase transitions take place when the Hawking temperature has an extremum and the heat capacity is singular. We demonstrate that black holes are thermodynamically stable in some range of event horizon radii where the heat capacity is positive. The BH shadow radii are calculated. It is shown that when increasing the nonlinearity parameter $\beta$ the BH shadow radius is decreased.


Author(s):  
S. Habib Mazharimousavi

Recently, the inverse electrodynamics model (IEM) was introduced and applied to find Reissner–Nordström black holes in the context of the general relativity coupled minimally with the nonlinear electrodynamics. The solution consists of both electric and magnetic fields as of the dyonic solutions. Here, in this note, we show that the IEM model belongs to a more general class of the nonlinear electrodynamics with [Formula: see text]. Here, [Formula: see text] is the energy momentum tensor of the nonlinear electrodynamic Lagrangian. Naturally, such a dyonic RN black hole solution is the solution for this general class.


2021 ◽  
Vol 81 (8) ◽  
Author(s):  
D. Batic ◽  
D. Asem Abuhejleh ◽  
M. Nowakowski

AbstractWe consider the possibility of having Dark Matter (DM) black holes motivated by the Einasto density profile. This generalizes both the noncommutative mini black hole model and allows DM to enter as the matter constituent which makes up the black hole. We show that it is possible to construct a black hole solution for each value of the Einasto index and for different values of the mass parameter, provided that the we work with the energy–momentum tensor of an anisotropic fluid. In particular, we achieve that by first considering the equation of state (EOS) $$p_r=-\rho $$ p r = - ρ . It turns out that the corresponding black hole solution exhibits a horizon structure similar to that of a Reissner–Nordström black hole and the central singularity is replaced by a regular de Sitter core. We also show that if the previous EOS is replaced by a nonlocal one, it is possible to construct a self-gravitating fuzzy DM droplet but also in this case, the radial pressure is negative. Finally, we contemplate scenarios of different dark matter black holes with moderate mass values which could have formed in galaxies. In particular, we probe the possibility whether such black holes could also be the central galactic objects.


2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Zi-Yu Tang ◽  
Bin Wang ◽  
Eleftherios Papantonopoulos

AbstractWe consider Maxwell-f(R) gravity and obtain an exact charged black hole solution with dynamic curvature in D-dimensions. Considering a spherically symmetric metric ansatz and without specifying the form of f(R) we find a general black hole solution in D-dimensions. This general black hole solution can reduce to the Reissner–Nordström (RN) black hole in D-dimensions in Einstein gravity and to the known charged black hole solutions with constant curvature in f(R) gravity. Restricting the parameters of the general solution we get polynomial solutions which reveal novel properties when compared to RN black holes. Specifically we study the solution in $$(3+1)$$ ( 3 + 1 ) -dimensions in which the form of f(R) can be solved explicitly giving a dynamic curvature and compare it with the RN black hole. We also carry out a detailed study of its thermodynamics.


2018 ◽  
Vol 14 (S342) ◽  
pp. 205-208
Author(s):  
Sergey Bogovalov

AbstractIn galactic nuclei (AGN), the kinetic energy flux of the jet may exceed the bolometric luminosity of the disk a few orders of magnitude. At the “cold” accretion the radiation from the disk is suppressed because the wind from the disk carries out almost all the angular momentum and the gravitational energy of the accreted material. We calculate an unavoidable radiation from such a disk and the ratio of the kinetic-to-bolometric luminosity from a super massive black hole in framework of the paradigm of the optically thick α-disk of Shakura & Sunyaev. The results confirm that the gravitational energy of the accreted material can be the only source of energy in AGNs.


2019 ◽  
Vol 34 (35) ◽  
pp. 1950231 ◽  
Author(s):  
M. Chabab ◽  
H. El Moumni ◽  
S. Iraoui ◽  
K. Masmar

The phase structure of charged anti-de Sitter black hole in massive gravity is investigated using the unstable circular photon orbits formalism, concretely we establish a direct link between the null geodesics and the critical behavior thermodynamic of such black hole solution. Our analysis reveals that the radius and the impact parameter corresponding to the unstable circular orbits can be used to probe the thermodynamic phase structure. We also show that the latter are key quantities to characterize the order of Van der Waals-like phase transition. Namely, we found a critical exponent around [Formula: see text]. All these results support further that the photon trajectories can be used as a useful and crucial tool to probe the thermodynamic black holes criticality.


2019 ◽  
Vol 35 (07) ◽  
pp. 2050029
Author(s):  
Amritendu Haldar ◽  
Ritabrata Biswas

In this paper, we consider the five-dimensional Myers–Perry black hole solution to study the thermodynamic properties and compare this with the thermodynamic behaviors of generalized uncertainty principle (GUP)-induced Myers–Perry solution. We study the existence of remnant quantities. Stability criteria are studied by observing the natures of temperature growth and sign changes in specific heat. We try to locate phase transitions. Moreover, we study the corresponding physical range for the GUP parameter and try to justify the value with the data predicted by different observations.


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