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arXiv · 2609.24400

Joule Thomson expansion of symmergent black holes in extended phase space

Saheb Soroushfar·Sayyed Mehrab Ramezani
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Abstract

We investigate the Joule Thomson expansion of a symmergent black hole within an extended phase-space formalism in which the thermodynamic pressure is introduced as an independent variable. The symmergent entropy contains the parameter alpha-hat, which modifies the enthalpy and thermodynamic volume relative to their standard forms. We show that the Joule Thomson coefficient depends only on the combination 8piP*r_+^2, leading to an inversion curve P_i = (pi/2) * I_i^2 that is independent of alpha-hat. The isenthalpic curves, however, retain a parametric dependence on alpha-hat, indicating that the symmergent sector affects the thermodynamic trajectories but not the inversion boundary itself. The inversion pressure and temperature are derived explicitly, and the cooling regime P > P_i is distinguished from the heating regime P < P_i. Since the effective geometry is asymptotically AdS-like for positive pressure, the results also admit a holographic reading, in which the Joule Thomson expansion corresponds to an isenthalpic process in the dual field theory. The results provide a consistent thermodynamic framework for symmergent black holes and clarify the role of the symmergent parameters in the Joule Thomson process.

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Saheb Soroushfar, Sayyed Mehrab Ramezani. 2026-09-21. Joule Thomson expansion of symmergent black holes in extended phase space. https://doi.org/10.22128/jhap.2026.3413.1220

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