More on QCD Ghost Dark Energy

TL;DR

This paper explores a dark energy model based on QCD ghost fields, showing it can explain late-time cosmic acceleration and fit current observational data as well as the standard Lambda-CDM model.

Contribution

It introduces a phenomenological dark energy model derived from QCD ghost fields and demonstrates its consistency with multiple cosmological observations.

Findings

The universe transitions to acceleration at redshift ~0.75.

The model fits growth factor data comparably to Lambda-CDM.

It predicts a late-time de Sitter phase.

Abstract

The difference between vacuum energy of quantum fields in Minkowski space and in Friedmann-Robterson-Walker universe might be related to the observed dark energy. The vacuum energy of the Veneziano ghost field introduced to solve the $U(1)_A$ problem in QCD is of the form, $ H+ {\cal O}(H^2)$. Based on this, we study the dynamical evolution of a phenomenological dark energy model whose energy density is of the form $\alpha H+\beta H^2$. In this model, the universe approaches to a de Sitter phase at late times. We fit the model with current observational data including SnIa, BAO, CMB, BBN, Hubble parameter and growth rate of matter perturbation. It shows that the universe begins to accelerate at redshift $z\sim 0.75$ and this model is consistent with current data. In particular, this model fits the data of growth factor well as the $\Lambda CDM$ model.