scholarly journals Thermal activation of thin-shells in anti-de Sitter black hole spacetime

2017 ◽  
Vol 2017 (7) ◽  
Author(s):  
Pisin Chen ◽  
Guillem Domènech ◽  
Misao Sasaki ◽  
Dong-han Yeom
Universe ◽  
2019 ◽  
Vol 5 (12) ◽  
pp. 225 ◽  
Author(s):  
Sergey I. Kruglov

A new modified Hayward metric of magnetically charged non-singular black hole spacetime in the framework of nonlinear electrodynamics is constructed. When the fundamental length introduced, characterising quantum gravity effects, vanishes, one comes to the general relativity coupled with the Bronnikov model of nonlinear electrodynamics. The metric can have one (an extreme) horizon, two horizons of black holes, or no horizons corresponding to the particle-like solution. Corrections to the Reissner–Nordström solution are found as the radius approaches infinity. As r → 0 the metric has a de Sitter core showing the absence of singularities, the asymptotic of the Ricci and Kretschmann scalars are obtained and they are finite everywhere. The thermodynamics of black holes, by calculating the Hawking temperature and the heat capacity, is studied. It is demonstrated that phase transitions take place when the Hawking temperature possesses the maximum. Black holes are thermodynamically stable at some range of parameters.


2011 ◽  
Vol 26 (39) ◽  
pp. 2923-2950 ◽  
Author(s):  
MARCO OLIVARES ◽  
JOEL SAAVEDRA ◽  
CARLOS LEIVA ◽  
JOSÉ R. VILLANUEVA

We study the motion of relativistic, electrically charged point particles in the background of charged black holes with nontrivial asymptotic behavior. We compute the exact trajectories of massive particles and express them in terms of elliptic Jacobi functions. As a result, we obtain a detailed description of particles orbits in the gravitational field of Reissner–Nordström (anti)-de Sitter black hole, depending of their charge, mass and energy.


2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Mariam Bouhmadi-López ◽  
Che-Yu Chen ◽  
Xiao Yan Chew ◽  
Yen Chin Ong ◽  
Dong-han Yeom

AbstractIn this paper, we show that a minimally coupled 3-form endowed with a proper potential can support a regular black hole interior. By choosing an appropriate form for the metric function representing the radius of the 2-sphere, we solve for the 3-form field and its potential. Using the obtained solution, we construct an interior black hole spacetime which is everywhere regular. The singularity is replaced with a Nariai-type spacetime, whose topology is $$\text {dS}_2 \times \text {S}^2$$ dS 2 × S 2 , in which the radius of the 2-sphere is constant. So long as the interior continues to expand indefinitely, the geometry becomes essentially compactified. The 2-dimensional de Sitter geometry appears despite the negative potential of the 3-form field. Such a dynamical compactification could shed some light on the origin of de Sitter geometry of our Universe, exacerbated by the Swampland conjecture. In addition, we show that the spacetime is geodesically complete. The geometry is singularity-free due to the violation of the null energy condition.


1998 ◽  
Vol 07 (01) ◽  
pp. 111-127 ◽  
Author(s):  
ZHONG CHAO WU

We discuss the Hawking theory of quantum cosmology with regard to approximation at the lowest order of the Planck constant. At this level, the quantum scenario will be reduced to its classical evolutions in real and imaginary times. We restrict our attention to the so-called real tunneling case. It can be shown that, even at this level, there still exist some quantum effects, the classical field equation may not hold at the transition surface. One can introduce the concept of constrained gravitational instanton. It may play some important role in the scenario of black hole creation in the inflationary background at the Planckian era of the universe. From the constrained gravitational instanton, the real tunneling can occur through different ways. Consequently, it will lead to the creation of different parts of the black hole spacetime in the de Sitter background. The global aspects of the black hole creation are discussed.


2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Ming Zhang ◽  
Jie Jiang

AbstractIn this work, we first calculate equations of motion for particles in the Kerr-Sen-de Sitter black hole spacetime. Then, in the eikonal regime, we analytically obtain the quasi-normal resonant modes of massless neutral scalar field perturbation and find its imaginary part to be characterized by the surface gravity of a near-extremal Kerr-Sen-de Sitter black hole with the Cauchy horizon approaching the event horizon. We further show that the Penrose strong cosmic censorship conjecture is thus respected in this spacetime with dilaton scalar field and axion pseudoscalar field.


2021 ◽  
Vol 81 (2) ◽  
Author(s):  
G. V. Kraniotis

AbstractWe investigate the redshift and blueshift of light emitted by timelike geodesic particles in orbits around a Kerr–Newman–(anti) de Sitter (KN(a)dS) black hole. Specifically we compute the redshift and blueshift of photons that are emitted by geodesic massive particles and travel along null geodesics towards a distant observer-located at a finite distance from the KN(a)dS black hole. For this purpose we use the killing-vector formalism and the associated first integrals-constants of motion. We consider in detail stable timelike equatorial circular orbits of stars and express their corresponding redshift/blueshift in terms of the metric physical black hole parameters (angular momentum per unit mass, mass, electric charge and the cosmological constant) and the orbital radii of both the emitter star and the distant observer. These radii are linked through the constants of motion along the null geodesics followed by the photons since their emission until their detection and as a result we get closed form analytic expressions for the orbital radius of the observer in terms of the emitter radius, and the black hole parameters. In addition, we compute exact analytic expressions for the frame dragging of timelike spherical orbits in the KN(a)dS spacetime in terms of multivariable generalised hypergeometric functions of Lauricella and Appell. We apply our exact solutions of timelike non-spherical polar KN geodesics for the computation of frame-dragging, pericentre-shift, orbital period for the orbits of S2 and S14 stars within the $$1^{\prime \prime }$$ 1 ″ of SgrA*. We solve the conditions for timelike spherical orbits in KN(a)dS and KN spacetimes. We present new, elegant compact forms for the parameters of these orbits. Last but not least we derive a very elegant and novel exact formula for the periapsis advance for a test particle in a non-spherical polar orbit in KNdS black hole spacetime in terms of Jacobi’s elliptic function sn and Lauricella’s hypergeometric function $$F_D$$ F D .


2020 ◽  
Vol 2020 (2) ◽  
Author(s):  
Koichi Nagasaki

Abstract We consider a defect solution in the anti-de Sitter (AdS) black hole spacetime. This is a generalization of the previous work [K. Nagasaki et al., J. High Energy Phys. 1201, 139 (2012)] to another spacetime. This system consists of D3- and D5-branes. The equation of motion for a sort of nonlocal operator, an “interface”, is given and its numerical solution is shown by the numerical calculation. We also consider a string extending between this interface and the boundary of the AdS spacetime. This corresponds to the quark–interface potential in the boundary theory of the bulk black hole spacetime. This result gives a new example of a holographic relation that includes the gauge flux in the probe D5-brane.


2016 ◽  
Vol 25 (07) ◽  
pp. 1650078 ◽  
Author(s):  
V. K. Oikonomou

In this paper, we investigate the conditions under which a Schwarzschild–de Sitter black hole spacetime is a solution of the mimetic [Formula: see text] gravity with Lagrange multiplier and potential. As we demonstrate, the resulting mimetic [Formula: see text] gravity is a slight modification of the ordinary [Formula: see text] gravity case, however the resulting perturbation equations are not in all cases identical to the ordinary [Formula: see text] gravity case. In the latter case, the perturbation equations are identical to the ones corresponding to the Reissner–Nordström anti-de Sitter black hole.


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