Dynamics of Dark Energy

Abstract

In this paper we review in detail a number of approaches that have been adopted to try and explain the remarkable observation of our accelerating Universe. In particular we discuss the arguments for and recent progress made towards understanding the nature of dark energy. We review the observational evidence for the current accelerated expansion of the universe and present a number of dark energy models in addition to the conventional cosmological constant, paying particular attention to scalar field models such as quintessence, K-essence, tachyon, phantom and dilatonic models. The importance of cosmological scaling solutions is emphasized when studying the dynamical system of scalar fields including coupled dark energy. We study the evolution of cosmological perturbations allowing us to confront them with the observation of the Cosmic Microwave Background and Large Scale Structure and demonstrate how it is possible in principle to reconstruct the equation of state of dark energy by also using Supernovae Ia observational data. We also discuss in detail the nature of tracking solutions in cosmology, particle physics and braneworld models of dark energy, the nature of possible future singularities, the effect of higher order curvature terms to avoid a Big Rip singularity, and approaches to modifying gravity which leads to a late-time accelerated expansion without recourse to a new form of dark energy.

Interactive mixture of inhomogeneous dark fluids driven by dark energy: a dynamical system analysis

“…However, for α < 0 (energy transfer from CDM to DE) the DE density became negative in phase space regions around the past attractor (irrespective of initial conditions), thus signalling an unphysical past evolution that is inconsistent with all observational data. This problem was already noticed in the literature with this type of CDM-DE mixtures based on FLRW metrics [1,2,7,8].…”

“…Current observational evidence supports the existence of an accelerated cosmic expansion, likely driven by an unknown form of matter-energy, generically denoted "dark energy" (DE), and usually described by suitable scalar fields or (phenomenologically) as a fluid with negative pressure [1][2][3][4]. Observations also point to the existence of cold dark matter (CDM) clustering around galactic halos, usually described in cosmological scales by pressure-less dust, while ordinary visible matter (baryons, electrons and neutrinos) and phoa e-mail: gizquierdos@uaemex.mx tons (radiation) comprise less than 5% of the total contents of cosmic mass-energy.…”

“…Several models of coupled dark sources can also be found in the literature motivated by particle physics, thermodynamics, etc. [1,2,[7][8][9][10][11].…”

“…The interplay of local and cosmic dynamics at all scales must comply with the observed anisotropy of the Cosmic Microwave Background (CMB) [1][2][3][4]. Evidently, this dynamics depends on the assumptions made on DE and CDM, which leads to a model dependent power spectrum that should be contrasted with observations at large scales and in structure formation (from data and from numerical simulations).…”

Об Изотропном Энергетическом Условии И Космологии

“…Тензор энергии-импульса для пространственно-однородной изотропной материи имеет диа-гональный вид T µν = diag(ρ, p, p, p). Условие w < −1 для материи с положительной плотностью энергии ρ подразумевает нарушение NEC [8], [9]. Поскольку экспе-риментальные данные не исключают возможности того, что w < −1 для темной 4 И. Я. АРЕФЬЕВА, И. В. ВОЛОВИЧ энергии, на долю которой по современным данным приходится около 70% всего ве-щества, исследование таких моделей привлекает большое внимание 1) .…”