On the cosmological evolution of Scalar Field Dark Matter in the $\texttt{CLASS}$ code: accuracy and precision of numerical solutions

TL;DR

This paper provides a detailed numerical analysis of scalar field dark matter evolution in the $ exttt{CLASS}$ code, demonstrating improved accuracy and discussing constraints on field mass using cosmological data.

Contribution

It introduces a precise numerical implementation of SFDM evolution in $ exttt{CLASS}$, enhancing accuracy and enabling constraints on the scalar field mass.

Findings

Numerical results agree well with original SFDM equations.

The approach yields better accuracy than previous methods.

Constraints on field mass are derived using MCMC likelihoods.

Abstract

We present a numerical analysis of the cosmological evolution of scalar field dark matter (SFDM) in the Boltzmann code $\texttt{CLASS}$, based on a dynamical system analysis of previous works. We show a detailed study of the evolution of the different dynamical variables, and in particular of the energy density and its corresponding linear perturbations. The numerical results are in good agreement with those of the original SFDM equations of motion, and have better accuracy than other approaches. In addition, we calculate the temperature and matter power spectra and discuss the reliability of their numerical results. We also give simple examples in which we can put constraints on the field mass using recent likelihoods incorporated in the Monte Carlo Markov Chain sampler $\texttt{MontePython}$.