https://doi.org/10.1140/epjc/s10052-022-10181-8
Regular Article - Theoretical Physics
Thermodynamic stability and P–V criticality of nonsingular-AdS black holes endowed with clouds of strings
1
Centre for Theoretical Physics, Jamia Millia Islamia, 110025, New Delhi, India
2
Department of Mathematics, Netaji Subhas University of Technology, 110078, New Delhi, India
3
Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Private Bag X54001, 4000, Durban, South Africa
4
Department of Mathematical Sciences, University of Zululand, Private Bag X1001, 3886, Kwa-Dlangezwa, South Africa
Received:
9
November
2021
Accepted:
1
March
2022
Published online:
15
March
2022
We investigate the extended phase space thermodynamics of nonsingular-AdS black holes minimally coupled to clouds of strings in which we consider the cosmological constant (
) as the pressure (P) of the black holes and its conjugate variable thermodynamical volume (V) of the black holes. Owing to the background clouds of strings parameter (a), we analyse the Hawking temperature, entropy and specific heat on horizon radius for fixed-parameter k. We find that the strings clouds background does not alter small/large black hole (SBH/LBH) phase transition but occurs at a larger horizon radius, and two second-order phase transitions occur at a smaller horizon radius. Indeed, the G–T plots exhibit a swallowtail below the critical pressure, implying that the first-order phase transition is analogous to the liquid–gas phase transition at a lower temperature and lower critical pressure. To further examine the analogy between nonsingular-AdS black holes and a liquid–gas system, we derive the exact critical points and probe the effects of a cloud of strings on 
criticality to find that the isotherms undergo liquid–gas like phase transition for 
at lower 
. We have also calculated the critical exponents identical with Van der Walls fluid, i.e., same as those obtained before for arbitrary other AdS black holes, which implies that the background clouds of strings do not change the critical exponents.
© The Author(s) 2022
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