A Unified Cosmological Dark Sector from a Bose-Einstein Condensate

TL;DR

This paper explores a cosmological model where a Bose-Einstein condensate of light bosons unifies dark matter and dark energy, with quantum effects playing a key role, and constrains the model using observational data.

Contribution

It proposes a unified dark sector model from a BEC, linking quantum potential to dark energy and deriving constraints on BEC properties from observations.

Findings

Quantum potential accounts for dark energy.

Back-reaction effects influence BEC mass.

Constraints on BEC mass derived from data.

Abstract

We examine the viability of cosmological solution(s) describing a unified picture of the dark side of the universe from a Bose-Einstein condensate (BEC) of light bosons. The energy density of the BEC, together with its quantum potential, can indeed account for such a unification, in the sense that the (dust-like) cold dark matter and the dark energy components emerge from the same source. In particular, the bulk of the dark energy can be attributed to the quantum potential, in the quantum corrected Raychaudhuri-Friedmann equation, when the `macroscopic' BEC wave-function is taken to be such that the corresponding probability density is construed as the energy density of the dusty fluid. However, there arises a purely quantum mechanical back-reaction effect, of even the visible baryons, on the effective dark energy and dark matter contents, which crucially determines the mass of the BEC. We determine the constraint on such a back-reaction, and hence on the BEC mass, from physical considerations, as well as estimate the same using recent observational data.