Bose-Einstein condensation of relativistic Scalar Field Dark Matter

TL;DR

This paper investigates the formation of a relativistic Bose-Einstein condensate in Scalar Field Dark Matter models, highlighting the necessity of particles and anti-particles and discussing cosmological implications.

Contribution

It demonstrates that a relativistic Bose-Einstein condensate can form in scalar field dark matter, emphasizing the role of particles and anti-particles in the early universe.

Findings

Condensate formation requires both particles and anti-particles.

The condensate is a relativistic phenomenon, contrary to common assumptions.

Implications for cosmology are discussed.

Abstract

Standard thermodynamical results of ideal Bose gases are used to study the possible formation of a cosmological Bose-Einstein condensate in Scalar Field Dark Matter models; the main hypothesis is that the boson particles were in thermal equilibrium in the early Universe. It is then shown that the only relevant case needs the presence of both particles and anti-particles, and that it corresponds to models in which the bosonic particle is very light. Contrary to common wisdom, the condensate should be a relativistic phenomenon. Some cosmological implications are discussed in turn.