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The peculiar case of the Viaggiu holographic dark energy

Somnath Saha, Subhajit Saha, Nilanjana Mahata

Abstract

We study the plausibility of a holographic dark energy (HDE) model using the form of horizon entropy proposed by Viaggiu in 2014. This form of entropy is a generalization of the usual Bekenstein-Hawking entropy, having an extra term arising due to the dynamical nature of horizons in an expanding universe. We examine this new HDE model in the context of a flat Friedmann-Lemaître-Robertson-Walker universe filled with two cosmic fluids -- dark matter in the form of dust and holographic dark energy generated by Viaggiu entropy. We consider the Hubble horizon and the future event horizon as characteristic length scales and study the evolution of the Universe within these frameworks. Our analysis reveals some intriguing findings that include a possible cosmic doomsday scenario in the future, and certain observations are in striking contrast to other HDE models studied in the literature.

The peculiar case of the Viaggiu holographic dark energy

Abstract

We study the plausibility of a holographic dark energy (HDE) model using the form of horizon entropy proposed by Viaggiu in 2014. This form of entropy is a generalization of the usual Bekenstein-Hawking entropy, having an extra term arising due to the dynamical nature of horizons in an expanding universe. We examine this new HDE model in the context of a flat Friedmann-Lemaître-Robertson-Walker universe filled with two cosmic fluids -- dark matter in the form of dust and holographic dark energy generated by Viaggiu entropy. We consider the Hubble horizon and the future event horizon as characteristic length scales and study the evolution of the Universe within these frameworks. Our analysis reveals some intriguing findings that include a possible cosmic doomsday scenario in the future, and certain observations are in striking contrast to other HDE models studied in the literature.
Paper Structure (7 sections, 41 equations, 2 figures)

This paper contains 7 sections, 41 equations, 2 figures.

Table of Contents

  1. Introduction
  2. A brief outline of the formulation of the Viaggiu entropy
  3. Viaggiu HDE with Hubble horizon as the IR cut-off
  4. The Non-interacting Case
  5. The Interacting Case
  6. Viaggiu HDE with the future event horizon as the IR cut-off
  7. Discussion and summary of the results

Figures (2)

  • Figure 1: The evolution of the density parameters of DM and VHDE as a function of the redshift $z$ corresponding to $\delta=0.4$ (left panel), $\delta=0.7$ (middle panel), and $\delta=0.9$ (right panel). We have imposed the initial condition $\Omega_d(x=-\hbox{ln}(1+z)=0) \equiv \Omega_{d0} \approx 0.7$.
  • Figure 2: The left and the right panels, respectively, show the evolution of the EoS of VHDE and the deceleration parameter as a function of the redshift $z$ for the three choices of $\delta$, viz. $\delta=0.4$, $\delta=0.7$, and $\delta=0.9$.