Sounds of instability from generalized QCD ghost dark energy

Abstract

We investigate about the stability of generalized QCD ghost dark energy model against perturbations in the FRW background. For this purpose, we use the squared sound speed $v_s^2$ whose sign determines the stability of the model. We explore the stability of this model in the presence/absence of interaction between dark energy and dark matter in both flat and non-flat geometry. In all cases we find almost a same result. Based on the square sound speed analysis, due to the existence of a free parameter in this model, the model is theoretically capable to lead a dark energy dominated stable universe. However, observational constraints rule out such a chance. In conclusion, we find evidences that the generalized ghost dark energy might can not lead to a stable universe favored by observations at the present time.

9 Pages, 3 Figures. arXiv admin note: text overlap with arXiv:1106.3504

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• Analysis of Generalized Ghost Pilgrim Dark Energy in Non-flat FRW Universe
• On An Interacting New Holographic Dark Energy Model: observational constraints
• Best values of parameters for interacting HDE with GO IR-cutoff in Brans-Dicke cosmology
• QCD ghost dark energy cannot (even roughly) explain the main features of the accepted cosmological paradigm
• Consistency of nonlinear interacting ghost dark energy with recent observations
• Generalized Ghost Pilgrim Dark Energy Fractal Cosmology with Observational Constraint
• Stability of HDE model with sign-changeable interaction in Brans-Dicke theory
• Revisiting Agegraphic Dark Energy in Brans-Dicke Cosmology