Interacting ghost dark energy in complex quintessence theory

Abstract

We employ a ghost model of interacting dark energy to obtain the equation of state $$\omega $$ ω for ghost energy density in an FRW universe in complex quintessence theory. We reconstruct the potential and study the dynamics of the scalar field that describes complex quintessence cosmology. We perform $$\omega -\omega '$$ ω - ω ′ analysis and stability analysis for both non-interacting and interacting cases and find that the same basic conclusion as for the real model, where $$\omega ' = d\omega / d ln a$$ ω ′ = d ω / d l n a . Taking account of the effect of the complex part and assuming the real part of the quintessence field to be a slow-rolling field, we conclude that the non-interacting model cannot describe the real universe since this will lead to fractional energy density $$\Omega _D > 1$$ Ω D > 1 , where $$\Omega _D$$ Ω D can be defined as the ratio of $$\rho _D$$ ρ D to $$\rho _{cr}$$ ρ cr . However, for the interacting case, if we take present $$\Omega _D =0.73$$ Ω D = 0.73 , then we can determine that $$b^2 = 0.0849$$ b 2 = 0.0849 , where $$b^2$$ b 2 is the interaction coupling parameter between matter and dark energy. In the real quintessence model, $$\Omega _D$$ Ω D and $$b^2$$ b 2 are independent parameters, whereas in the complex quintessence model, we conclude that there is a relationship between these two parameters.

Tsallis and Kaniadakis holographic dark energy with Complex Quintessence theory in Brans-Dicke cosmology

“…In this case, the variation of figure per parameter δ seems more tangible. The values of the free parameter are specified in [27] and these results are in agreement with the case reviewed by the authors in [39]. For example, in the case of interacting ghost dark energy in complex quintessence theory, the free parameters were not observed, and one can obtain the change of the figure only for different values of ω D .…”

“…In figure (2) we analyze ω D − ω ′ D for the interacting case according to the free parameters which Also, the overlap and positive region of the figure is in the range (−0.7 < ω D < −0.5), which is different from the non-interacting case and is somewhat close to the results of [39]. When the parameter δ is between 1 and 2, the figures obtained up to the range ω D > −0.5 are negative, and still, their distance is very close and narrower for different values of b 2 and δ.…”

“…Of course, by setting the free parameters as mentioned in the text and placing Ω D = 0.73, we can calculate various values for the coupling parameter b 2 . In [39] authors measured the value of this parameter b 2 as 0.0849 with a similar process. Here by setting free parameters, we can determine the value of this coupling parameter b 2 too.…”

“…This model has been used to describe the structure of dark energy through the correspondence between ghost dark energy and the complex quintessence. In this respect, the authors of [39] concluded that by considering the complex part of the scalar field and taking the real part of the quintessence field to be a "slow-rolling" field, a non-interacting case can not describe the real universe. Because in their calculation the Ω D is greater than 1.…”

Tachyon model of Tsallis holographic dark energy

“…In fact, in ref. [48], we have already considered the possibility of ghost dark energy as a complex quintessence field. We intend to explore further complex scalar field possibilities as dark energy candidates and form a framework of these candidates.…”