Early dark energy and its interaction with dark matter

Abstract

We study a class of early dark energy models which has substantial amount of dark energy in the early epoch of the universe. We examine the impact of the early dark energy fluctuations on the growth of structure and the CMB power spectrum in the linear approximation.Furthermore we investigate the influence of the interaction between the early dark energy and the dark matter and its effect on the structure growth and CMB. We finally constrain the early dark energy model parameters and the coupling between dark sectors by confronting to different observations.

Dark matter and dark energy interactions: theoretical challenges, cosmological implications and observational signatures

“…DE perturbation are not longer negligible and contribute to the ISW effect. The effect on models based on a field theory description have also been discussed in [315].…”

“…Earlier studies on DM/DE interaction used WMAP, and additionally other data sets on CMB temperature anisotropies, to set upper limits on the strength of the DM/DE coupling [272,274,152,384,413,386,295,334,118,119,175,177,178] or to constrain the cross-section of DM/DE interactions [416]. More recently, Planck CMB data have been used to constrain interacting models with different kernels discussed in the literature: Q = Hξ 1 ρ c [118,387], Q = Hξ 2 ρ d [118,334,420,421,76], [118,143,315]. Other couplings have also been discussed; [335] has shown that the data provides a moderate Bayesian evidence in favor of an interacting vacuum model.…”

“…For the sake of simplicity in our subsequent discussion, we will review only models with a DE EoS parameter ω d = const. The results for a variable EoS have been reported in [315,415]. We restrict our analysis to the models that satisfy the stability condition (Sec.…”

Interacting cosmic fluids and phase transitions under a holographic modeling for dark energy

“…2 We see that T de > T dm in the range −0.2 < z < 1.86, i.e., when Q > 0 and T de < T dm for z > 1.86, i.e., when Q < 0, in accord to the second law. However, in the range −0.39 < z < −0.2, when Q < 0, the quotient T de /T dm diverges and Q (z) can be written in the form…”

“…Certain observational evidence seems to indicate that dark energy and dark matter, considered as dominant components of the cosmic fluid, can interact [1][2][3][4]. Perhaps an interaction between dynamical vacuum energy and matter is also possible [5] or a scenario where a particle creation mechanism which can lead to cosmic acceleration [6].…”