On the quantum origin of a dark universe

TL;DR

This paper proposes that dark matter and dark energy originate from a quantum potential associated with a Bose-Einstein condensate of ultralight bosons, offering a unified explanation for the dark sector and addressing the coincidence problem.

Contribution

It introduces a quantum corrected cosmological model with a BEC that unifies dark matter and dark energy, resolving the coincidence problem and estimating boson mass from observations.

Findings

Dark energy emerges as a cosmological constant from quantum potential.

The model provides a natural explanation for the coincidence of dark matter and dark energy densities.

Estimated boson mass aligns with other theoretical bounds.

Abstract

It has been shown beyond reasonable doubt that the majority (about 95%) of the total energy budget of the universe is given by the dark components, namely Dark Matter and Dark Energy. What constitutes these components remains to be satisfactorily understood however, despite a number of promising candidates. An associated conundrum is that of the coincidence, i.e. the question as to why the Dark Matter and Dark Energy densities are of the same order of magnitude at the present epoch, after evolving over the entire expansion history of the universe. In an attempt to address these, we consider a quantum potential resulting from a quantum corrected Raychaudhuri/Friedmann equation in presence of a cosmic fluid, which is presumed to be a Bose-Einstein condensate (BEC) of ultralight bosons. For a suitable and physically motivated macroscopic ground state wavefunction of the BEC, we show that a unified picture of the cosmic dark sector can indeed emerge, thus resolving the issue of the coincidence. The effective Dark energy component turns out to be a cosmological constant, by virtue of a residual homogeneous term in the quantum potential. Furthermore, comparison with the observational data gives an estimate of the mass of the constituent bosons in the BEC, which is well within the bounds predicted from other considerations.