Cosmological constraints on the multiscalar field dark matter model

The main aim of this paper is to provide cosmological constraints on the multiscalar field dark matter model, in which we assume the dark matter is made up of different ultralight scalar fields. As a first approximation, we consider they are real and do not interact with each other. We study the equations for both the background and perturbations for N -fields and present the evolution of the density parameters, the mass power spectrum, and the cosmic microwave background spectrum. In particular, we focus on two scalar fields with several combinations for the potentials V(0) = 1/2m2002, V(0) = m20f2[1 + cos(0/f)], and V(0) = m20f2[cosh(0/f) - 1], however, the work, along with the code, could be easily extended to more fields. We use the data from baryon acoustic oscillation, big bang nucleosynthesis, Lyman -a forest, and supernovae to find constraints on the sampling parameters for the cases of a single field and double field, along with the Bayesian evidence. We found that some combinations of the potentials get penalized through the evidence, however, for others there is a preference as good as for the cold dark matter.

Automated summary

The paper provides cosmological constraints on the multiscalar field dark matter model and presents the results for different combinations of potentials. Through analyzing multiple data sources, constraints on the sampling parameters for both single-field and double-field cases are obtained.