scholarly journals Quantum superradiance on static black hole space-times

2020 ◽  
Vol 811 ◽  
pp. 135904
Author(s):  
Visakan Balakumar ◽  
Elizabeth Winstanley ◽  
Rafael P. Bernar ◽  
Luís C.B. Crispino
Keyword(s):  
2003 ◽  
Vol 12 (01) ◽  
pp. 121-127 ◽  
Author(s):  
REMO RUFFINI ◽  
LUCA VITAGLIANO

The mass-energy formula of black holes implies that up to 50% of the energy can be extracted from a static black hole. Such a result is reexamined using the recently established analytic formulas for the collapse of a shell and the expression for the irreducible mass of a static black hole. It is shown that the efficiency of energy extraction process during the formation of the black hole is linked in an essential way to the gravitational binding energy, the formation of the horizon and the reduction of the kinetic energy of implosion. Here a maximum efficiency of 50% in the extraction of the mass energy is shown to be generally attainable in the collapse of a spherically symmetric shell: surprisingly this result holds as well in the two limiting cases of the Schwarzschild and extreme Reissner–Nordström space–times. Moreover, the analytic expression recently found for the implosion of a spherical shell to an already formed black hole leads to a new exact analytic expression for the energy extraction which results in an efficiency strictly less than 100% for any physical implementable process. There appears to be no incompatibility between General Relativity and Thermodynamics at this classical level.


1991 ◽  
Vol 8 (10) ◽  
pp. 548-550 ◽  
Author(s):  
Zhao Zheng ◽  
Dai Xianxin

2020 ◽  
Vol 29 (03) ◽  
pp. 2050025 ◽  
Author(s):  
Mykola M. Stetsko

Scalar–tensor theory of gravity with nonlinear electromagnetic field, minimally coupled to gravity is considered and static black hole solutions are obtained. Namely, power-law and Born–Infeld nonlinear Lagrangians for the electromagnetic field are examined. Since the cosmological constant is taken into account, it allowed us to investigate the so-called topological black holes. Black hole thermodynamics is studied, in particular temperature of the black holes is calculated and examined and the first law of thermodynamics is obtained with help of Wald’s approach.


2019 ◽  
Vol 28 (12) ◽  
pp. 1950160
Author(s):  
M. B. Tataryn ◽  
M. M. Stetsko

Static black hole with the Power Maxwell invariant (PMI), Born–Infeld (BI), logarithmic (LN), exponential (EN) electromagnetic fields in three-dimensional spacetime with cosmological constant was studied. It was shown that the LN and EN fields represent the Born–Infeld type of nonlinear electrodynamics. It the framework of General Relativity the exact solutions of the field equations were obtained, corresponding thermodynamic functions were calculated and the [Formula: see text] criticality of the black holes in the extended phase-space thermodynamics was investigated.


1998 ◽  
Vol 13 (03) ◽  
pp. 239-252 ◽  
Author(s):  
W. A. SABRA

An algorithm for constructing general static black hole configuration for the theory of N=2, d= 5 supergravity coupled to an arbitrary number of Abelain vector multiplets is given. The underlying very special geometry structure plays a major role in this construction. From the viewpoint of M-theory compactified on a Calabi–Yau threefold, these black holes are identified with BPS winding states of the membrane around two-cycles of the Calabi–Yau threefold, and thus are of importance in the probing of the phase transitions in the moduli space of M-theory compactified on a Calabi–Yau threefold.


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