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C. L. Ahmed Rizwan

Publications and source records attributed to C. L. Ahmed Rizwan.

22 records · Page 2Linked to original sources

Joule-Thomson Expansion of Regular Bardeen AdS Black Hole Surrounded by Static Anisotropic Quintessence Field

In the present paper, we investigate the required anisotropy of an exact regular Bardeen black hole characterized by its mass $M$, the nonlinear parameter $g$, the quintessence field parameter $a$ in anti-de sitter spacetime with a static quintessence matter field. We also show that the relative pressure anisotropy, equation of state and the pressure depends on radial coordinate, reflecting the required anisotropy for Bardeen black hole in the quintessence background. Next, we analyze the Joule-Thompson ($JT$) expansion of the black hole spacetime. Treating the cosmological constant as thermodynamic pressure $P$ and its conjugate quantity as thermodynamic volume $V$ we derive the equation of state connecting Hawking temperature and various black hole parameters. We study the $JT$ expansion in the regular Bardeen AdS black holes in the quintessence background through the analysis of inversion temperature and isenthalpic curves. We derive the $JT$ coefficient $μ$, and use them to plot the inversion and isenthalpic curves. We discuss the effect of quintessence parameter $a$ and $ω_q$ on the $JT$ coefficient and inversion temperature, especially with the case of $ω_q=-1$ and $ω_q=-\frac{1}{3}$. Our analysis shows that quintessence dark energy affects the inversion point $(T_i,P_i)$ .

gr-qc↗

Critical Behaviour and Microscopic Structure of Charged AdS Black Hole with a Global Monopole in Extended and Alternate Phase Spaces

A detailed discussion on phase transition and microscopic structure of charged AdS black hole with a global monopole is presented in both extended and alternate phase spaces. In the analysis of critical behaviour, the classical van der Waals analogy is drawn from isotherms which is followed by Gibbs free energy study and coexistence curves. In both spaces, the symmetry breaking parameter $η$ acts as a hindrance for critical behaviour. The crux of van der Waals like behaviour is investigated by looking at the microscopic structure of the black hole via thermodynamic Ruppeiner geometry. The Ruppeiner invariant scalar behaves differently in extended and alternate spaces. The monopole parameter influences the microscopic structure of the black hole, which in turn, affects the critical behaviour. The effect is significant at the maximal strength of the monopole parameter.

gr-qc↗

Regular Bardeen AdS Black Hole as a Heat Engine

We investigate the thermodynamic phase transitions and heat engine efficiency in regular Bardeen AdS black hole. Interpreting cosmological constant as thermodynamic pressure, we study the thermodynamics using T S and P v plots. Specific heat studies also carried out in detail. A first order phase transition in evident from these studies. These are followed by the construction of a heat engine considering the black hole as working substance. The efficiency is obtained via a thermodynamic cycle in the P V plane which receives and ejects heat. The heat engine efficiency is improved by adding a quintessence field. The analytical expression for heat engine efficiency is derived in terms of quintessence dark energy parameter. This result may deepen our understanding about thermodynamics of asymptotically AdS black holes.

gr-qc↗

Joule-Thomson expansion in AdS black hole with a global monopole

In this paper, we investigate the Joule Thomson effects for AdS black holes with a global monopole. We study the effect of the global monopole parameter η on the inversion temperature and isenthalpic curves. The obtained result is compared with Joule Thomson expansion of van der Waals fluid and the equivalence were noted. Phase transition occuring in the extended phase space of this black hole is analogous to van der Waals gas. Our study shows that global monopole parameter η plays a very important role in Joule Thomson expansion.

gr-qc↗