Friedmann cosmology with hyperfluids of constant equation of state

TL;DR

This paper explores cosmological models within metric-affine gravity, emphasizing the role of hypermomentum, and analyzes how its degrees of freedom influence the universe's evolution under the cosmological principle.

Contribution

It introduces the dynamics of hypermomentum in metric-affine cosmology, focusing on cases where hypermomentum is proportional to matter density and examining their impact on cosmic evolution.

Findings

Hyperfluid hypermomentum can significantly affect cosmological dynamics.

Proportional hypermomentum models show varied evolution depending on associated indexes.

The study provides insights into alternative gravity theories with additional matter sources.

Abstract

We discuss some aspects of cosmology in metric-affine theories of gravity where metric and affine connection are independent variables. Such constructions, apart from the usual energy-momentum tensor, have an additional source, that of hypermomentum. Working with the cosmological principle assumption, we investigate the dynamics of the hypermomentum's degrees of freedom. In particular, we focus on the case where these degrees of freedom are proportional to the matter density and discuss the cosmological evolution depending on their associated indexes.