Nobuyoshi Komatsu

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

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.

Cosmic microwave background radiation temperature in a dissipative universe

The relationship between the cosmic microwave background radiation temperature and the redshift, i.e., the

Entropic Cosmology from a Thermodynamics Viewpoint

Tensuremath{-}z

Nonequilibrium process of self-gravitating N-body systems and quasi-equilibrium structure using normalized q-expectation values for Tsallis' generalized entropy

relation, is examined in a phenomenological dissipative model. The model contains two constant terms, as if a nonzero cosmological constant

Performance of a Vertical Axis Wind Turbine with Variable-Pitch Straight Blades utilizing a Linkage Mechanism

mathrm{ensuremath{Lambda}}

Thermodynamic properties of an evaporation process in self-gravitating N -body systems

and a dissipative process are operative in a homogeneous, isotropic, and spatially flat universe. The

Numerical irreversibility in self-gravitating small N-body systems

Tensuremath{-}z

Negative specific heat in self-gravitating N -body systems enclosed in a spherical container with reflecting walls

relation is derived from a general radiative temperature law, as appropriate for describing nonequilibrium states in a creation of cold dark matter model. Using this relation, the radiation temperature in the late Universe is calculated as a function of a dissipation rate ranging from

Flow Characteristics of a Plane Jet with an Extended Lip-Plate and Serrated Tabs

stackrel{texttildelow{}}{ensuremath{mu}}=0

Overspeed Control of a Variable-Pitch Vertical-Axis Wind Turbine by Means of Tail Vanes

, corresponding to a nondissipative lambda cold dark matter model, to