Speaker
Description
We review the Little Sibling of the Big Rip (LSBR) model, by introducing a new parameterization designed to alleviate its negative energy behavior at early times. The main objective of this parameterization is to improve the theoretical and observational viability of the LSBR model and provide an alternative to the ΛCDM model. The proposed parameterization is constrained using cosmic microwave background (CMB) data, Dark Energy Spectroscopic Instrument (DESI DR2) measurements, and several Type Ia supernovae (SNIa) datasets, including PantheonPlus, Union3, and DES-Y5. The combination of CMB and DESI DR2 data indicates that, owing to the recent inferred value of the equation of state parameter, our model behaves like a phantom dark energy. However, when different SNIa datasets are included, the model shifts toward a quintessence like behavior. From a statistical perspective, using the combined CMB + DESI DR2 + DES-Y5 dataset, we find that the evidence in favor of the proposed parameterization is enhanced by approximately 2.1σ relative to the ΛCDM model. We further show that the inferred nature of this new LSBR parameterization has significant implications for the future evolution and ultimate fate of the Universe.
| Topic | Cosmology, Dark energy, Equation of state, Observational data |
|---|