# Dark energy and dark matter unification from dynamical space time: observational constraints and cosmological implications

## TL;DR

This paper investigates a dynamical space-time model that unifies dark energy and dark matter, analyzing its theoretical stability and testing its compatibility with recent cosmological observations, finding it largely consistent with data.

## Contribution

It introduces a novel dynamical space-time framework unifying dark energy and dark matter, with stability analysis and observational constraints.

## Key findings

- DSC models can produce cosmic acceleration and stable late-time attractors.
- The models are in good agreement with current cosmological data.
- One model shows a slight deviation from standard Lambda CDM, near 1.5 sigma confidence.

## Abstract

A recently proposed Dynamical Space-time Cosmology (DSC) that unifies dark energy and dark matter is studied. The general action of this scenario includes a Lagrange multiplier, which is coupled to the energy momentum tensor and a scalar field which is different from quintessence. First for various types of potentials we implement a critical point analysis and we find solutions which lead to cosmic acceleration and under certain conditions to stable late-time attractors. Then the DSC cosmology is confronted with the latest cosmological data from low-redshift probes, namely measurements of the Hubble parameter and standard candles (Pantheon SnIa, Quasi-stellar objects). Performing an overall likelihood analysis and using the appropriate information criteria we find that the explored DSC models are in very good agreement with the data. We also find that one of the DSC models shows a small but non-zero deviation from $\Lambda$ cosmology, nevertheless the confidence level is close to $\sim 1.5\sigma$.