Bayesian comparison of interacting scenarios

Abstract

We perform a Bayesian model selection analysis for different classes of phenomenological coupled scenarios of dark matter and dark energy with linear and non-linear interacting terms. We use a combination of some of the latest cosmological data such as type Ia supernovae (SNe Ia), cosmic chronometers (CC), cosmic microwave background (CMB) and two sets of baryon acoustic oscillations measurements, namely, 2-dimensional angular measurements (BAO2) and 3-dimensional angle-averaged measurements (BAO3). We find weak and moderate evidence against two-thirds of the interacting scenarios considered with respect to ΛCDM when the full joint analysis is considered. About one-third of the models provide a description to the data as good as the one provided by the standard model. Our results also indicate that either SNe Ia, CC or BAO2 data by themselves are not able to distinguish among interacting models or ΛCDM but the standard BAO3 measurements and the combination with the CMB data are indeed able to discriminate among them. We find that evidence disfavoring interacting models is weaker when we use BAO2 (data claimed to be almost model-independent) instead of the standard BAO3 measurements. These results help select classes of viable and non-viable interacting models in light of current data.

Bayesian comparison of interacting modified holographic Ricci dark energy scenarios

“…The Bayesian inference (based on the Bayes' theorem) is a robust statistical technique for parameter estimation and model selection widely used in the study of cosmological scenarios [74,80]. The Bayes' theorem relates the posterior probability P for a set of parameters , given the data D, described by a model M,…”

“…In particular, in Ref. [80] inconclusive evidence was found in studying a class of interacting models when compared to CDM and considering background data.…”

Looking for interactions in the cosmological dark sector

“…On the other hand, there has been a growing interest in models with interaction between the dark components [13][14][15][16][17][18][19][20][21][22][23]. A basic hypothesis of standard cosmology is that pressureless matter is conserved, which is mathematically expressed by the well-known evolution law ρ m ∝ a −3 , where ρ m is the matter density and a the cosmological scale factor.…”

Model-independent reconstruction of dark sector interactions

“…Physically, Q represents an energy exchange between the dark components, which necessarily violates adiabaticity at the same time that it brings about important consequences on the model predictions. Currently, a number of analysis show that some particular classes of interacting models are able to provide a good description of the data [9][10][11][12][13][14][15][16][17][18][19][20], sometimes alleviating some of the tensions of the standard cosmology [21][22][23][24][25][26][27][28]. From the theoretical point of view, however, critiques to these models do exist, being mainly related to the absence of a natural guidance from fundamental physics on the coupling term, which leads to a phenomenological choice of Q [29][30][31][32].…”