scholarly journals Diffeomorphism Symmetries near a timelike surface in black hole spacetime

Author(s):  
Mousumi Maitra ◽  
Debaprasad Maity ◽  
Bibhas Ranjan Ranjan Majhi
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.


2019 ◽  
Vol 35 (10) ◽  
pp. 2050061
Author(s):  
Z. Luo ◽  
X. G. Lan

It is suggested that the dispersion relation might be corrected at higher energy scales and lead to the deformed Hamilton–Jacobi equation. In this paper, we use the correction to investigate the fermion tunneling radiation for Demianski–Newman black hole spacetime, and the result shows that the corresponding Hawking temperature and the black hole entropy are related to the angular parameters of the black hole coordinates.


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