Cosmology with an Action Principle

TL;DR

This paper revisits the Friedman universe using a novel approach based on an action principle for matter, aligning with standard results at low densities and proposing a reinterpretation of vacuum energy.

Contribution

It introduces a new theoretical framework for cosmology using an action principle for matter, offering alternative insights into the Friedman universe and vacuum energy.

Findings

Results agree with standard theory at low densities

Proposes replacing vacuum energy with external force

Applies the same theory to ideal star configurations

Abstract

The Friedman universe is re-examined in a context that is non-standard only in that the properties of matter are postulated in the form of an action principle. Applications to equilibrium configurations of ideal stars have already been reported. In this paper we apply the same theory to a fresh examination of the Friedman universe. The results agree with standard theory in the case of low densities. A suggestion is made to replace "vacuum energy" by "external force".