Accelerated expansion and the virial theorem

TL;DR

This paper proposes that energy release during dark matter structure formation could eject high-velocity particles, creating a pressure that mimics dark energy and potentially explains the universe's accelerated expansion.

Contribution

It introduces a novel mechanism where dark matter ejection effects produce a pressure that may account for cosmic acceleration, challenging the need for a cosmological constant.

Findings

Estimated effect size comparable to observed acceleration

Suggests ejected dark matter particles influence cosmic dynamics

Highlights need for more precise calculations of the effect

Abstract

When dark matter structures form and equilibrate they have to release a significant amount of energy in order to obey the virial theorem. Since dark matter is believed to be unable to radiate, this implies that some of the accreted dark matter particles must be ejected with high velocities. These ejected particles may then later hit other cosmological structures and deposit their momentum within these structures. This induces a pressure between the cosmological structures which opposes the effect of gravity and may therefore mimic a cosmological constant. We estimate the magnitude of this effect and find that it may be as large as the observed accelerated expansion. Our estimate is accurate only within a few orders of magnitude. It is therefore important to make a much more careful calculation of this redshift dependent effect, before beginning to interpret the observed accelerated expansion as a time dependent generalization of a cosmological constant.