Unification of Dark Matter and Dark Energy in a Modified Entropic Force Model

TL;DR

This paper proposes a modified entropic force model based on a Debye approach to explain the universe's accelerated expansion without dark energy, fitting observational data and unifying several cosmic phenomena.

Contribution

It introduces a one-dimensional Debye model into the entropic force framework, providing a new unified explanation for cosmic acceleration, galaxy dynamics, and Pioneer anomaly.

Findings

Best-fit model parameters: ζ ≈ 10^{-9}, Ω_{m0} = 0.224

Model fits observational data with χ² ≈ 591.156

Universe's age consistent with previous estimates

Abstract

In Verlinde's entropic force scenario of gravity, Newton's laws and Einstein equations can be obtained from the first pinciples and general assumptions. However, the equipartition law of energy is invalid at very low temperatures. We show clearly that the threshold of the equipartition law of energy is related with horizon of the universe. Thus, a one-dimension Debye (ODD) model in the direction of radius of the modified entropic force (MEF) maybe suitable in description of the accelerated expanding universe. We present a Friedmann cosmic dynamical model in the ODD-MEF framework. We examine carefully constraints on the ODD-MEF model from the Union2 compilation of the Supernova Cosmology Project (SCP) collaboration, the data from the observation of the large-scale structure (LSS) and the cosmic microwave background (CMB), i.e. SNe Ia+LSS+CMB. The combined numerical analysis gives the best-fit value of the model parameters $\zeta\simeq10^{-9}$ and $\Omega_{m0}=0.224$, with $\chi_{min}^2=591.156$. The corresponding age of the universe agrees with the result of D. Spergel {\it et al.}\cite{Spergel2003} at 95% confidence level. The numerical result also yields an accelerated expanding universe without invoking any kind of dark energy. Taking $\zeta(\equiv 2\pi \omega_D/H_0)$ as a running parameter associated with the structure scale $r$, we obtain a possible unified scenario of the asymptotic flatness of the radial velocity dispersion of spiral galaxies, the accelerated expanding universe and the Pioneer 10/11 anomaly in the entropic force framework of Verlinde.