Constraints on alternative models to dark energy

TL;DR

This paper investigates alternative models to dark energy by analyzing a generalized modified Friedmann equation, using supernova and WMAP data to constrain these models and study the universe's transition from deceleration to acceleration.

Contribution

It introduces and constrains three novel modified Friedmann models using observational data, exploring the universe's acceleration without dark energy.

Findings

Models are consistent with supernova and WMAP data.

Transition from deceleration to acceleration is characterized in each model.

Modified equations can explain acceleration without dark energy.

Abstract

The recent observations of type Ia supernovae strongly support that the universe is accelerating now and decelerated in the recent past. This may be the evidence of the breakdown of the standard Friemann equation. We consider a general modified Friedmann equation. Three different models are analyzed in detail. The current supernovae data and the Wilkinson microwave anisotropy probe data are used to constrain these models. A detailed analysis of the transition from the deceleration phase to the acceleration phase is also performed.