Dynamics of holographic vacuum energy in the DGP model

TL;DR

This paper investigates the evolution of holographic vacuum energy within the DGP model, exploring different IR cut-offs and their implications for dark energy behavior, including potential crossing of the phantom divide and compatibility with observational data.

Contribution

It introduces a holographic vacuum energy framework in the DGP model considering various IR cut-offs and analyzes their effects on dark energy dynamics and observational consistency.

Findings

Vacuum energy can act as dark energy in certain IR cut-off choices.

The equation of state may cross -1, indicating phantom-like behavior.

Model aligns with current supernova and baryon oscillation data within 1σ.

Abstract

We consider the evolution of the vacuum energy in the DGP model according to the holographic principle under the assumption that the relation linking the IR and UV cut-offs still holds in this scenario. The model is studied when the IR cut-off is chosen to be the Hubble scale $H^{-1}$, the particle horizon $R_{\rm ph}$ and the future event horizon $R_{\rm eh}$, respectively. And the two branches of the DGP model are also taken into account. Through numerical analysis, we find that in the cases of $H^{-1}$ in the (+) branch and $R_{\rm eh}$ in both branches, the vacuum energy can play the role of dark energy. Moreover, when considering the combination of the vacuum energy and the 5D gravity effect in both branches, the equation of state of the effective dark energy may cross -1, which may lead to the Big Rip singularity. Besides, we constrain the model with the Type Ia supernovae and baryon oscillation data and find that our model is consistent with current data within $1\sigma$, and that the observations prefer either a pure holographic dark energy or a pure DGP model