Evidence for interacting dark energy from BOSS

Abstract

The result presented by the BOSS-SDSS Collaboration measuring the baryon acoustic oscillations of the Lyman-alpha forest from high-redshift quasars indicates a 2.5σ departure from the standard Λ-cold-dark-matter model. This is the first time that the evolution of dark energy at high redshifts has been measured, and the current results cannot be explained by simple generalizations of the cosmological constant. We show here that a simple phenomenological interaction in the dark sector provides a good explanation for this deviation, naturally accommodating the Hubble parameter obtained by BOSS, H(z = 2.34) = 222 ± 7 km s −1 Mpc −1 . By performing a global fit of the parameters with the inclusion of this new data set together with the Planck data for the interacting model, we are able to show that some interacting models have constraints for H(2.34) and DA(2.34) that are compatible with the ones obtained by the BOSS Collaboration, showing a better concordance than ΛCDM. We also show that the interacting models that have a small positive coupling constant, which helps alleviate the coincidence problem, are compatible with the cosmological observations. Adding the likelihood of these new baryon acoustic oscillations data shows an improvement in the global fit, although it is not statistically significant. The coupling constant could not be fully constrained by the data sets used, but the dark energy equation of state shows a slight preference for a value different from a cosmological constant.PACS numbers: 95.36.+x, 98.80.Es, 95.30.Sf, 98.80.Jk

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

“…An interacting DE appears as a simple and efficient solution to explain the BOSS result. If DE and DM interact and the former transfers energy to the latter, as required to alleviate the coincidence problem (see sec 2.7) and indicated by the data [118], it would explain the value of the Hubble parameter, H(z = 2.34) = 222 ± 7kms −1 Mpc −1 , obtained by the BOSS collaboration, value that is smaller than the expectation from ΛCDM [143]. It would explain the discrepancy of the angular diameter distance at high redshifts.…”

Echo of interactions in the dark sector

“…See [12,13] for general review. The late-time interaction in the dark sector has recently been investigated in various studies [14][15][16][17][18][19][20][21][22][23][24][25][26] in different contexts.…”

Perfect fluid in Lagrangian formulation due to generalized three-form field

“…The study of dark energy and dark matter coupling has been widely investigated in order to describe a way out from the cosmic coincidence problem [8][9][10][11][12]. Moreover, the observation also provide a hint for the existence of the coupling [13]. However, in order to recover the standard thermodynamics equations, the Lagrangian must involve at least five independent functions.…”