Faculty Publications

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Publications by NITK Faculty

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Author: search.filters.author.Ahmed Rizwan, C.L.Subject: search.filters.subject.Phase transitions

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    The Role of Global Monopole in Joule–Thomson Effect of AdS Black Hole
    (Springer Science and Business Media Deutschland GmbH, 2021) Naveena Kumara, A.; Ahmed Rizwan, C.L.; Ajith, K.M.
    We study the throttling process of the AdS black hole with a global monopole in the extended phase space. In the approach followed, the cosmological constant and the black hole mass are identified with the thermodynamic pressure and enthalpy, respectively. We investigate the dependency of the inversion temperature and isenthalpic curves on the global monopole parameter η. Our study shows a close resemblance between the phase transition of the black hole in the extended phase space and Van der Waals fluid. The presence of global monopole plays an important role in the throttling process. © 2021, Springer Nature Singapore Pte Ltd.
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    Effect of dark energy in geometrothermodynamics and phase transitions of regular Bardeen AdS black hole
    (Springer, 2019) Ahmed Rizwan, C.L.; Naveena Kumara, A.; Rajani, K.V.; Vaid, D.; Ajith, K.M.
    We study the thermodynamics and geometrothermodynamics of regular Bardeen-AdS black hole with quintessence. The thermodynamics of the black hole is scrutinised using Temperature–Entropy (T–S), Pressure–Volume (P–v) and Gibbs energy plots, which indicates a critical behaviour. The behaviour is also confirmed from the divergence of specific heat against entropy, which shows a second-order phase transition. Furthermore, we observe that the quintessence state parameter ? shifts the transition point to lower entropy values. Using the concept of thermodynamic Ruppeiner and Weinhold geometry, we calculated the thermodynamic curvature scalar RR and RW in the quintessence dark energy regime (?= - 2 / 3 ). While these curvature scalars enable us to identify the critical behaviour, they do not show divergence at the phase transition points observed in specific heat study. To resolve this puzzle, we have adopted the method of geometrothermodynamics proposed by Hernando Quevedo. Choosing a Legendre invariant ‘Quevedo’ metric, the curvature scalar RQ shows singularity at the same point as seen in the specific heat divergence. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.