Do Bound Structures Brake Cosmic Acceleration?

TL;DR

This study examines how bound cosmic structures influence the scalar field's equation of state, revealing that superclusters notably affect cosmic acceleration, with potential corrections of around 3%.

Contribution

It provides an analytical and numerical analysis of the coupling effects between quintessence fields and matter structures on large scales.

Findings

Superclusters have the most significant impact on the scalar field's equation of state.

Coupling strength increases the correction to the homogeneous equation of state.

Estimated corrections across the Hubble volume are approximately 3%.

Abstract

In this paper we investigate the impact of the coupling between a quintessence field and clustered matter on the average equation of state of the scalar field. We take the NFW profile to be characteristic of bound structures on galactic and cluster scales, and the isothermal distribution to hold for objects on supercluster scales. Solving analytically for the scalar-field profile, we find that the greatest impact on the equation of state comes from the superclusters. Employing numerical case studies, we verify this effect and probe its dependence on the evolutionary state of the supercluster. An estimate across the Hubble volume yields corrections to the homogeneous equation of state of ~3%, increasing with coupling strength.