Cosmological model from the holographic equipartition law with a modified Rényi entropy

• Main Author: Nobuyoshi Komatsu
• Format: Article
• Language: English
• Published: SpringerOpen 2017-04-01
• Series: European Physical Journal C: Particles and Fields
• Subjects: Entropy; Dark Energy; Cosmological Model; Cosmological Constant Problem; Flat Universe
• Online Access: http://link.springer.com/article/10.1140/epjc/s10052-017-4800-2

Abstract Cosmological equations were recently derived by Padmanabhan from the expansion of cosmic space due to the difference between the degrees of freedom on the surface and in the bulk in a region of space. In this study, a modified Rényi entropy is applied to Padmanabhan’s ‘holographic equipartition law’, by regarding the Bekenstein–Hawking entropy as a nonextensive Tsallis entropy and using a logarithmic formula of the original Rényi entropy. Consequently, the acceleration equation including an extra driving term (such as a time-varying cosmological term) can be derived in a homogeneous, isotropic, and spatially flat universe. When a specific condition is mathematically satisfied, the extra driving term is found to be constant-like as if it is a cosmological constant. Interestingly, the order of the constant-like term is naturally consistent with the order of the cosmological constant measured by observations, because the specific condition constrains the value of the constant-like term.