Stability analysis of agegraphic dark energy in Brans-Dicke cosmology

TL;DR

This paper investigates the stability of agegraphic dark energy within Brans-Dicke cosmology, analyzing how the universe's stability evolves over time and how observational data constrains the model.

Contribution

It provides a stability analysis of agegraphic dark energy in Brans-Dicke theory, including observational constraints and the evolution of the universe's state.

Findings

Universe may start from an unstable state and become stable in the future.

Best fitted models show no intermediate saddle point.

Dark energy exhibits phantom behavior, modified to quintessence by cold dark matter.

Abstract

Stability analysis of agegraphic dark energy in Brans-Dicke theory is presented in this paper. We constrain the model parameters with the observational data and thus the results become broadly consistent with those expected from experiment. Stability analysis of the model without best fitting shows that universe may begin from an unstable state passing a saddle point and finally become stable in future. However, with the best fitted model, There is no saddle intermediate state. The agegraphic dark energy in the model by itself exhibits a phantom behavior. However, contribution of cold dark matter on the effective energy density modifies the state of teh universe from phantom phase to quintessence one. The statefinder diagnosis also indicates that the universe leaves an unstable state in the past, passes the LCDM state and finally approaches the sable state in future.