arXiv subjects

Izzet Sakalli

Publications and source records attributed to Izzet Sakalli.

22 records · Page 2Linked to original sources

arXiv2022

Modified Cosmic Chaplygin AdS Black Hole

In this paper, we construct a new charged AdS black hole with modified cosmic Chaplygin gas (MCCG). In comparison to the previous model (modified Chaplygin AdS black hole) existed in the literature, we now have two new parameters: the cosmic parameter and the black hole's electric charge. We examine the asymptotically charged AdS black hole thermodynamics with MCCG under the assumption of a negative cosmological constant as a thermodynamics pressure. Using MCCG, we developed a new solution to Einstein's AdS black hole field equations.The mass parameter, volume, electric potential, entropy, and temperature of the charged AdS black hole have all been computed. We also study the various energy conditions for the MCCG as a source fluid of AdS black hole. For some restrictions on the involved parameters, we show that these conditions are met. Then, we study the thermodynamical stability, critical points, and Joule-Thompson expansion for the back hole obtained. We reveal that while the existence of cosmic parameter yields to a complete stable mode, its absence gives rise to some unstable regions. Then, using MCCG, we treat the obtained black hole's thermodynamics as a heat engine and calculate the work done as well as the heat engine's maximum efficiency in the Carnot cycle. The work done, the efficiency, and the Rankine cycle's efficiency are also investigated. All of the findings are graphically depicted and discussed.

gr-qc↗

arXiv2018

Gravitational Lensing Under the Effect of Weyl and Bumblebee Gravities: Applications of Gauss-Bonnet Theorem

In this paper, we use the Gauss Bonnet theorem to obtain the deflection angle by the photons coupled to Weyl tensor in a Schwarzschild black hole and Schwarzschild-like black hole in bumblebee gravity in the weak limit approximation. To do so, we first calculate the corresponding optical metrics, and then we find the Gaussian curvature to use in Gauss-Bonnet theorem, which is first done by Gibbons and Werner. Hence, in the leading order terms we show the deflection angle, that is affected by the coupling between the photon and Weyl tensor, and there is a deviation from the deflecting angle as compared with Schwarzschild black hole with Schwarzschild-like black hole in bumblebee gravity. Moreover, we investigate the deflection angle by Einstein-Rosen type wormhole in Weyl gravity and in bumblebee gravity. Interestingly, the deflection angle by Einstein-Rosen type wormhole in bumblebee gravity is found as larger than the the deflection angle by Einstein-Rosen type wormhole in Weyl gravity.

gr-qc↗

arXiv2018

Quasinormal Modes of a Schwarzschild Black Hole Immersed in an Electromagnetic Universe

We study the quasinormal modes (QNMs) of the Schwarzschild black hole immersed in an electromagnetic (em) universe. The immersed Schwarzschild black hole (ISBH) is originated from the metric of colliding em waves with double polarization [Class. Quantum Grav. 12, 3013 (1995)]. The perturbation equations of the scalar fields for the ISBH geometry are written in the form of separable equations. We show that these equations can be transformed to the confluent Heun's equations, for which we are able to use the known techniques to perform the analytical quasinormal (QNM) analysis of the solutions. Furthermore, we employ numerical methods [Mashhoon and $6^{th}$-order Wentzel-Kramers-Brillouin (WKB)] to derive the QNMs. The results obtained are discussed and depicted with the appropriate plots.

physics.gen-ph↗

arXiv2003

Cosmic Strings Coupled With a Massless Scalar Field

A scalar field generalization of Xanthopoulos's cylindrically symmetric solutions of the vacuum Einstein equation is obtained. The obtained solution preserves the properties of the Xanthopoulos solution, which are regular on the axis, asymptotically flat and free from the curvature singularities. The solution describes stable, infinite length of rotating cosmic string interacting with gravitational and scalar waves.

gr-qc↗