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H. El Moumni

Publications and source records attributed to H. El Moumni.

43 records · Page 3Linked to original sources

Behavior of Quasinormal Modes and high dimension RN-AdS Black Hole phase transition

In this work we use the quasinormal frequencies of a massless scalar perturbation to probe the phase transition of the high dimension charged-AdS black hole. The signature of the critical behavior of this black hole solution is detected in the isobaric as well as in isothermal process. This paper is a natural generalization of \cite{base} to higher dimensional spacetime. More precisely our study shows a clear signal for any dimension $d$ in the isobaric process. As to the isothermal case, we find out that this signature can be affected by other parameters like the pressure and the horizon radius. We conclude that the quasinormal modes can be an efficient tool to investigate the first order phase transition, but fail to disclose the signature of the second order phase transition.

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Maxwell's equal-area law for Gauss-Bonnet Anti-de Sitter black holes

Interpreting the cosmological constant Λas a thermodynamic pressure and its conjugate quantity as a thermodynamic volume, we study the Maxwell's equal area law of higher dimensional Gauss-Bonnet-AdS black holes in extended phase space. These black hole solutions critically behave like Van der Waals systems. It has been realized that below the critical temperature T_c the stable equilibrium is violated. We show through calculations that the critical behaviors for the uncharged black holes only appear in d=5. For the charged case, we analyse solutions in d = 5 and d = 6 separately and find that, up to some constrains, the critical behaviors only appear in the spherical topology. Using the Maxwell's construction, we also find the isobar line for which the liquid-gas-like phases coexist.

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On Thermodynamics of 2d Black Holes in Brane Inflationary Potentials

Inspired from the inflation brane world cosmology, we study the thermodynamics of a black hole solution in two dimensional dilaton gravity with an arctangent potential background. We first derive the two dimensional black hole geometry, then we examine its asymptotic behaviors. More precisely, we find that such behaviors exhibit properties appearing in some known cases including the Anti de Sitter and the Schwarzchild black holes. Using the complex path method, we compute the Hawking radiation. The entropy function can be related to the value of the potential at the horizon.

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On Thermodynamical Behaviors of Kerr-Newman AdS Black Holes

We reconsider the study of critical behaviors of Kerr-Newman AdS black holes in four dimensions. The study is made in terms of the moduli space parameterized by the charge Q and the rotation parameter a, relating the mass M of the black hole and its angular momentum J via the relation a=J/M. Specifically, we discuss such thermodynamical behaviors in the presence of a positive cosmological constant considered as a thermodynamic pressure and its conjugate quantity as a thermodynamic volume. The equation of state for a charged RN-AdS black hole predicts a critical universal number depending on the (Q,a) moduli space. In the vanishing limit of the a parameter, this prediction recovers the usual universal number in four dimensions. Then, we find the bounded regions of the moduli space allowing the consistency of the model with real thermodynamical variables.

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On Thermodynamics of AdS Black Holes in Arbitrary Dimensions

Considering the cosmological constant $Λ$ as a thermodynamic pressure and its conjugate quantity as a thermodynamic volume as proposed in Kubiznak and Mann (2012), we discuss the critical behavior of charged AdS black hole in arbitrary dimensions $d$. In particular, we present a comparative study in terms of the spacetime dimension $d$ and the displacement of critical points controlling the transition between the small and the large black holes. Such behaviors vary nicely in terms of $d$. Among our result in this context consists in showing that the equation of state for a charged RN-AdS black hole predicts an universal number given by $\frac{2d-5}{4d-8}$. The three dimensional solution is also discussed.

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On Schwarzschild black holes in a D-dimensional noncommutative space

This work aims to implement the idea of noncommutativity in the subject of black holes. Its principal contents deal with a study of Schwarzschild black holes in a D-dimensional noncommutative space. Various aspects related to the non commutative extension are discussed and some non trivial results are derived.

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