  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.
