Neutrino decoupling and the transition to cold dark matter

TL;DR

This paper revisits the role of neutrinos in cosmology, arguing that they could be the cold dark matter particles instead of hot dark matter, based on quantum uncertainty considerations.

Contribution

It introduces a quantum uncertainty-based approach to neutrino decoupling, challenging longstanding assumptions about neutrinos as hot dark matter.

Findings

Neutrino decoupling occurred about half a second after the Big Bang.

Arguments against neutrinos as dark matter have loopholes or are incorrect.

Neutrinos may be viable candidates for cold dark matter.

Abstract

About 40 years ago, the neutrino was ruled out as the dark matter particle based on several arguments. Here I use the well-established concept of quantum uncertainties of position and momentum to describe the decoupling of neutrinos from the primordial plasma, which took place about half a second after the Big Bang. In this way I show that the main arguments against the neutrino are either wrong or have loopholes, and conclude that the neutrino urgently needs to be reconsidered, not as a 'hot', but as the 'cold' dark matter particle.