2011/09/07 by Ujjal Debnath, Mubasher Jamil, Surajit Chattopadhyay
Physics and Astronomy · #Action (physics) #Advanced Mathematical Theories and Applications #Apparent horizon #Cosmology #Cosmology and Gravitation Theories #Event horizon #First law #First law of thermodynamics #Power law #Second law of thermodynamics #Statistical Mechanics and Entropy #Universe #physics.gen-ph
paper · pdf · doi:10.1007/s10773-011-0961-1
published as Int. J. Theor. Phys. (2012) 51:812-837 · 24 pages, 32 figures, Accepted in Int. J. Theor. Phys
arxiv created 2011/09/07 · openalex publication_date 2011/09/28 · arxiv updated 2012/02/14 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
In the framework of Fractional Action Cosmology (FAC), we study the generalized second law of thermodynamics for the Friedmann Universe enclosed by a boundary. We use the four well-known cosmic horizons as boundaries namely, apparent horizon, future event horizon, Hubble horizon and particle horizon. We construct the generalized second law (GSL) using and without using the first law of thermodynamics. To check the validity of GSL, we express the law in the form of four different scale factors namely emergent, logamediate, intermediate and power law. For Hubble, apparent and particle horizons, the GSL holds for emergent and logamediate expansions of the universe when we apply with and without using first law. For intermediate scenario, the GSL is valid for Hubble, apparent, particle horizons when we apply with and without first law. Also for intermediate scenario, the GSL is valid for event horizon when we apply first law but it breaks down without using first law. But for power law expansion, the GSL may be valid for some cases and breaks down otherwise.