1301.6832 (Ricardo Garcia-Salcedo et al.)

QCD ghost dark energy can not (even roughly) explain the main features
of the accepted cosmological paradigm    [PDF]

Ricardo Garcia-Salcedo, Tame Gonzalez, Israel Quiros, Michael Thompson-Montero

We explore the whole phase space of the so called Veneziano/QCD ghost dark energy models where the dynamics of the inner trapping horizon is neglected and also the more realistic models where the time-dependence of the horizon is taken into consideration. Both cases with and without additional non-gravitational interaction between cold dark matter and ghost dark energy are scrutinized. We pay special attention to the choice of phase space variables leading to bounded and compact phase space so that no critical point of physical interest is missing. It is demonstrated that ghost dark energy is not a suitable candidate to explain the presently accepted cosmological paradigm since no critical point associated with neither dark matter nor radiation dominance is found in the phase space relevant to the model. A transient stage of matter dominance -- responsible for the observed amount of cosmic structure -- is an essential ingredient of the accepted cosmological paradigm. The above drawback is in addition to the well known problem with classical instability against small perturbations of the background density originated from negativity of the sound speed squared.

View original: http://arxiv.org/abs/1301.6832