https://doi.org/10.1140/epjc/s10052-024-12484-4
Regular Article - Theoretical Physics
Amended FRW universe: thermodynamics and heat engine
1
Department of Mathematics, Heritage Institute of Technology, 700107, Kolkata, India
2
Department of Mathematics, Indian Institute of Engineering, Science and Technology, Shibpur, 711 103, Howrah, India
3
Centre for Cosmology, Astrophysics and Space Science, GLA University, 281406, Mathura, UP, India
Received:
11
September
2023
Accepted:
28
January
2024
Published online:
7
February
2024
Thermodynamics of non-flat Amended Friedmann–Robertson–Walker (AFRW) universe with cosmological constant as thermodynamic pressure is studied. The unified first law of thermodynamics, the Clausius relation and the gravity equations yield entropy on the dynamic apparent horizon. Temperature, volume, pressure, enthalpy, Gibb’s free energy and Helmholtz’s free energies, and specific heat capacity with constant pressure of the universe are calculated in terms of surface area of dynamic apparent horizon. The study shows a non-negative Joule–Thomson coefficient, indicating the cooling nature of the AFRW universe. Inversion pressure and inversion temperature are expressed in terms of the surface area of the apparent horizon. Finally, the thermodynamical AFRW universe is considered as a heat engine. Work done for the Carnot engine is derived with maximum efficiency, and a new engine is also considered for which the work done, and its efficiency are calculated for AFRW universe.
© The Author(s) 2024
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