Particle vs. future event horizon in interacting holographic dark energy model

TL;DR

This paper compares particle and future event horizons in an interacting holographic dark energy model, showing the former respects thermodynamics and predicts multiple phase transitions, avoiding the big rip.

Contribution

It demonstrates that using the particle horizon instead of the future event horizon yields a thermodynamically consistent model with multiple phase transitions.

Findings

Future event horizon model violates the second law of thermodynamics.

Particle horizon model allows ω=-1 crossing consistent with thermodynamics.

Model predicts a transition from phantom to quintessence, avoiding big rip.

Abstract

By choosing the future event horizon as the horizon of the flat FLRW universe, we show that although the interacting holographic dark energy model is able to explain the phantom divide line crossing, but the thermodynamics second law is not respected in this model. We show that if one takes the particle event horizon as the horizon of the universe, besides describing $\omega=-1$ crossing in a consistent way with thermodynamics second law, he is able to determine appropriately the ratio of dark matter to dark energy density at transition time. In this approach, after the first transition from quintessence to phantom, there is another transition from phantom to quintessence phase which avoids the big rip singularity.