Multi-fluid Theory and Cosmology: A Convective Variational Approach to Interacting Dark-Sector

TL;DR

This paper develops a relativistic variational formalism for multi-fluid interactions, specifically focusing on dark matter, dark energy, and ordinary matter, to better understand their entrainment phenomena in cosmology.

Contribution

It extends existing multi-fluid formalism to explicitly model interactions involving dark matter and dark energy in a cosmological context.

Findings

Formalism captures entrainment effects in dark-sector interactions

Provides a new framework for relativistic multi-fluid cosmology

Enhances understanding of dark matter and dark energy coupling

Abstract

This article examines the foundation of the recently developed relativistic variational formalism[1]. Our work is heavily based on [2, 27] which extends this approach to the multi-fluid theory and examines its utility in astrophysics and cosmology. Unlike the extension to the formalism mentioned above, that looks at the general interaction between different types of matter, we use the formalism to examine the interaction involving, ordinary matter, dark matter (DM) and dark energy (DE). We focus on entrainment phenomena involving the dark-sector constituents.