Effective field description of the Anton-Schmidt cosmic fluid

TL;DR

This paper models the universe using the Anton-Schmidt fluid within the Debye approximation, describing cosmic evolution without a cosmological constant and fitting observational data with a novel scalar field approach.

Contribution

It introduces a new effective field description of the Anton-Schmidt cosmic fluid, linking it to scalar fields and providing a comprehensive analysis of cosmic epochs.

Findings

Anton-Schmidt model fits low-redshift data well

Model describes both early and late universe epochs

Statistical comparison favors Anton-Schmidt over ΛCDM in certain cases

Abstract

The effective theory of the Anton-Schmidt cosmic fluid within the Debye approximation is investigated. In this picture, the universe is modeled out by means of a medium without cosmological constant. In particular, the Anton-Schmidt representation of matter describes the pressure of crystalline solids under deformations imposed by isotropic stresses. The approach scheme is related to the fact that the universe deforms under the action of the cosmic expansion itself. Thus, we frame the dark energy term as a function of scalar fields and obtain the corresponding dark energy potential $V(\varphi)$. Different epochs of the universe evolution are investigated in terms of the evolution of $\varphi$. We show how the Anton-Schmidt equation of state is capable of describing both late and early epochs of cosmic evolution. Finally, numerical bounds on the Anton-Schmidt model with $n=-1$ are derived through a Markov Chain Monte Carlo analysis on the combination of data coming from type Ia Supernovae, observations of Hubble parameter and baryon acoustic oscillations. Statistical comparison with the $\Lambda$CDM model is performed by the AIC and BIC selection criteria. Results are in excellent agreement with the low-redshift data. A further generalization of the model is presented to satisfy the theoretical predictions at early-stage cosmology.