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Mahamat Saleh

Publications and source records attributed to Mahamat Saleh.

7 recordsLinked to original sources

Thermodynamic Phase Transition and global stability of the Regular Hayward Black hole Surrounded by Quintessence

In this work, we investigate the thermodynamic and the stability of the regular Hayward black hole surrounded by quintessence. Using the metric of the black hole surrounded by quintessence and the new approach of the holographic principle, we derive the expression of the Unruh Verlinde temperature. Hawking temperature and specific heat are derived using the first law of black holes thermodynamics. Gibbs free energy is also evaluated. The behaviors of these quantities show that, the quantum effects represented by the parameter $β$ induces a decreasing of the Hawking temperature of the black hole, and that decrease is accentuated when increasing the magnitude of $β$ and the normalization factor $a$ related to the density of quintessence. For the lower entropies, the black hole passes from the unstable phase to the stable one by a first order thermodynamics phase transition. When increasing the entropy, a second phase transition occurs. This new phase transition is a second-order thermodynamics phase transition and brings the black hole to unstable state. It results that, when increasing of magnitude of $β$, the phase transition points are shifted to the higher entropies. Moreover, the phenomena of phase transitions are preserved by adding the quintessence. Furthermore, when increasing the normalization factor of quintessence, the first order transition point is shifted to higher entropies, while the second-order thermodynamics phase transition point is shifted to lower entropies.

gr-qc

Thermodynamics and Phase transition from regular Bardeen black hole

In this paper, thermodynamics and phase transition are investigated for the regular Bardeen black hole. Considering the metric of the Bardeen spacetime, we derived the Unruh-Verlinde temperature. Using the first law of thermodynamics, we derived the expression of the specific heat and plot its behavior. It results that the magnetic monopole charge $β$ reduces the temperature and induces a thermodynamics phase transition in the spacetime. Moreover, when increasing $β$, the transition point moves to higher entropy.

gr-qc

Energy distribution and thermodynamics of the quantum-corrected Schwarzschild black hole

In this work, energy distribution and thermodynamics are investigated in the Schwarzschild black hole spacetime when considering corrections due to quantum vacuum fluctuations. The Einstein and Møller prescriptions were used to derive the expressions of the energy in the background. The temperature and heat capacity were also derived. The results show that due to the quantum fluctuations in the background of the Schwarzschild black hole, all the energies increase and Einstein energy differs from Møller's one. Moreover, when increasing the quantum correction factor ($a$), the difference between Einstein and Møller energies, the Unruh-Verlinde temperature as well as the heat capacity of the black hole increase while the Hawking temperature remains unchanged.

gr-qc

Thermodynamics and Phase transition of the Reissner-Nordström Black Hole surrounded by quintessence

We investigate thermodynamics and Phase transition of the Reissner-Nordström black hole surrounded by quintessence. Using thermodynamical laws of black holes, we derive the expressions of some thermodynamics quantities for the Reissner-Nordström black hole surrounded by quintessence. The variations of the temperature and heat capacity with the entropy were plotted for different values of the state parameter related to the quintessence, $ω_{q}$, and the normalization constant related to the density of quintessence $c$. We show that when varying the entropy of the black hole a phase transition is observed in the black hole. Moreover, when increasing the density of quintessence, the transition point is shifted to lower entropy and the temperature of the black hole decreases.

gr-qc

Quasinormal modes and Hawking radiation of a Reissner-Nordström black hole surrounded by quintessence

We investigate quasinormal modes (QNMs) and Hawking radiation of a Reissner-Nordström black hole sur-rounded by quintessence. The Wentzel-Kramers-Brillouin (WKB) method is used to evaluate the QNMs and the rate of radiation. The results show that due to the interaction of the quintessence with the background metric, the QNMs of the black hole damp more slowly when increasing the density of quintessence and the black hole radiates at slower rate.

gr-qc

Hawking radiation from a five-dimensional Lovelock black hole

We investigate Hawking radiation from a five-dimensional Lovelock black hole using the Hamilton-Jacobi method. The behavior of the rate of radiation is plotted for various values of the ultraviolet correction parameter and the cosmological constant. The results show that, owing to the ultraviolet correction and the presence of dark energy represented by the cosmological constant, the black hole radiates at a slower rate in comparison to the case without ultraviolet correction or cosmological constant. Moreover, the presence of the cosmological constant makes the effect of the ultraviolet correction on the black hole radiation negligible.

gr-qc

Quasinormal modes of a quantum-corrected Schwarzschild black hole: gravitational and Dirac perturbations

In this work, quasinormal modes (QNMs) of the Schwarzschild black hole are investigated by taking into account the quantum fluctuations. Gravitational and Dirac perturbations were considered for this case. The Regge-Wheeler gauge and the Dirac equation were used to derive the perturbation equations of the gravitational and Dirac fields respectively and the third order Wentzel-Kramers-Brillouin (WKB) approximation method is used for the computing of the quasinormal frequencies. The results show that due to the quantum fluctuations in the background of the Schwarzschild black hole, the QNMs of the black hole damp more slowly when increasing the quantum correction factor (a), and oscillate more slowly.

gr-qc