Power spectrum for the Bose-Einstein condensate dark matter

TL;DR

This paper investigates how Bose-Einstein condensate dark matter influences cosmic structure formation, showing that it causes a small but detectable increase in large-scale matter power spectrum depending on particle mass.

Contribution

It introduces a model of BEC dark matter affecting large-scale cosmological perturbations using neo-Newtonian cosmology, highlighting observable effects in the matter power spectrum.

Findings

BEC dark matter causes an excess of power at large scales.

The effect depends on the condensate particle mass, between 15meV and 700meV.

Small but perceptible impact on the matter power spectrum.

Abstract

We assume that dark matter is composed of scalar particles that form a Bose-Einstein condensate (BEC) at some point during the cosmic evolution. Afterwards, cold dark matter is in the form of a condensate and behaves slightly different from the standard dark matter component. We study the large scale perturbative dynamics of the BEC dark matter in a model where this component coexists with baryonic matter and cosmological constant. The perturbative dynamics is studied using neo- Newtonian cosmology (where the pressure is dynamically relevant for the homogeneous and isotropic background) which is assumed to be correct for small values of the sound speed. We show that BEC dark matter effects can be seen in the matter power spectrum if the mass of the condensate particle lies in the range 15meV < m < 700meV leading to a small, but perceptible, excess of power at large scales.