2024/03/19 by Soumya Chakrabarti, Chakrabarti, Soumya · 1 citation
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Cosmology and Gravitation Theories #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th) #Mathematical Physics (math-ph) #Pattern Formation and Solitons (nlin.PS) #Statistical Mechanics and Entropy
paper · pdf · doi:10.48550/arxiv.2403.12622
openalex publication_date 2024/03/19 · openalex created_date 2024/03/21 · openalex updated_date 2026/07/28
Motivated by the notion that the mathematics of gravity can be reproduced from a statistical requirement of maximal entropy, we study the consequence of introducing an entropic source term in the Einstein-Hilbert action. For a spatially homogeneous cosmological system driven by this entropic source and enveloped by a time evolving apparent horizon, we formulate a modified version of the second law of thermodynamics. An explicit differential equation governing the internal entropy profile is found. Using a Hessian matrix analysis of the internal entropy we check the thermodynamic stability for a ΛCDM cosmology, a unified cosmic expanson and a non-singular ekpyrotic bounce. We find the mathematical condition for a second order phase transition during these evolutions from the divergence of specific heat at constant volume. The condition is purely kinematic and quadratic in nature, relating the deceleration parameter and the jerk parameter that chalks out an interesting curve on the parameter space. This condition is valid even without the entropic source term and may be a general property of any phase transition.