Generalized entropies and the expansion law of the universe

Abstract

We suggest that using the first law of thermodynamics is a convenient method to obtain a correct form of the expansion law of the universe \cite{T. Padmanabhan1}. We will, then, use this idea to obtain the expansion law for a Kodama observer. By using the expansion law for a Kodama observer, we can obtain the dynamic equation of the FRW universe for deformed Horava-Lifshitz gravity. The use of the first law of thermodynamics also leads to a new approach for obtaining the Friedmann equations for f(R) and scalar tensor gravities.

7 pages

References in corpus (7)

• Quantum Gravity at a Lifshitz Point
• Spectral Dimension of the Universe in Quantum Gravity at a Lifshitz Point
• Thermodynamic Behavior of Friedmann Equation at Apparent Horizon of FRW Universe
• Unified First Law and Thermodynamics of Apparent Horizon in FRW Universe
• Hawking Radiation of Apparent Horizon in a FRW Universe
• Friedmann equations from emergence of cosmic space
• Emergence of Space and Spacetime Dynamics of Friedmann-Robertson-Walker Universe

Cited by in corpus (5)

• Emergence of cosmic space and its connection with thermodynamic principles
• First Law of Thermodynamics and Emergence of Cosmic Space in a Non-Flat Universe
• Friedmann equations from GUP-modified equipartition law
• Cosmological scenario based on the first and second laws of thermodynamics: Thermodynamic constraints on a generalized cosmological model
• From MOND entropy to extended uncertainty principles: A unified framework