Semi-holographic model revisited

TL;DR

This paper revisits a semi-holographic dark energy model, deriving an explicit analytical solution without a cosmological constant that fits supernova data but violates energy conditions, questioning its physical viability.

Contribution

The paper provides an explicit analytical solution to the semi-holographic dark energy model without a cosmological constant, highlighting its inconsistency with physical energy conditions.

Findings

Derived an explicit analytical solution fitting supernova data

Found the solution violates all energy conditions

Questions the physical viability of the model

Abstract

In a recent work Zhang, Li and Noh [Phys. Lett. B {\bf 694}, 177 (2010)]proposed a model for dark energy assuming this component strictly obeys the holographic principle. They performed a dynamical system analysis, finding a scaling solution which is helpful to solve the coincidence problem. However they need explicitly a cosmological constant. In this paper we derive an explicit analytical solution, without $\Lambda$, that shows agreement with the Supernovae data. However this solution is not physical because violate all the energy conditions.