Multiple dark matter as a self‐regulating mechanism for dark sector interactions

Abstract

A wide range of astrophysical and cosmological observations support the evidence that the energy density of the Universe is presently largely dominated by particles and fields that do not belong to the standard model of particle physics. Such cosmic dark sector appears to be made of two distinct entities capable to account for the growth of large-scale structures and for the observed acceleration of the expansion rate of the Universe, respectively dubbed dark matter and dark energy. Nevertheless, the fundamental nature of these two dark components has so far remained mysterious. In the currently accepted scenario dark matter is associated to a single new massive and weakly interacting particle beyond the standard model, while dark energy is assumed to be a simple cosmological constant. However, present cosmological constraints and the absence of a direct detection and identification of any dark matter particle candidate leave room to the possibility that the dark sector of the Universe be actually more complex than it is normally assumed. In particular, more than one new fundamental particle could be responsible for the observed dark matter density in the Universe, and possible new interactions between dark energy and dark matter might charac-*

Multifield coupled quintessence

“…It is immediately obtained that i x The matter dominated solution is the fixed point characterized by x i , y i = 0, (or y = 0) and which essentially means that the partial derivative with respect to the field φ i of the sum of all the dark matter contributions must vanish. This solution was discussed in a number of recent publications for a single field system and two dark matter components with symmetric couplings [45][46][47][48]. For the simple system of two fields and two dark matter components we obtain that the field must settle at the bottom of a valley defined by the flat direction in the φ 1 -φ 2 plane,…”

“…The possibility that a scalar field is indeed coupled to more than a single dark matter component has been raised recently in Ref. [44,45] and the phenomenology of such a set up was investigated and compared to observations in Refs. [46][47][48].…”

Testing dark matter clustering with redshift space distortions

“…[17][18][19][20][21] multiple dark matter, e.g. [22][23][24][25][26][27], atomic dark matter [28], resonant dark matter [29], cannibal dark matter [30], etc. Section II investigates the effect of a deviation in the dark matter clustering strength on the density perturbation growth equations.…”

Linear density perturbations in multifield coupled quintessence

“…In a series of recent papers [20,21,24], perturbations in the McDE model have been calculated numerically and compared with present and future large scale structure experiments. Taking this line of investigation, one can model the dark sector of the universe as being made up of N fluids interacting with M scalar fields.…”

“…One example is coupled quintessence. In this model a scalar field, which makes up the dark energy (DE) component of the universe and produces acceleration, is coupled to a pressureless dark matter fluid [10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Recent extensions which have been investigated include Multicoupled Dark Energy (McDE) (see e.g.…”