Speaker
Description
The sign-switching cosmological constant cold dark matter ($\Lambda_{\rm s}$CDM) cosmology has emerged as a promising new paradigm, showing notable success in reconciling observational data from diverse probes and in addressing major cosmological tensions, such as the $H_0$, $S_8$, and $\gamma$ (growth index) discrepancies. The model introduces a minimal but non-trivial modification to the standard $\Lambda$CDM framework by positing a rapid Anti-de Sitter (AdS) to de Sitter (dS) transition in the late universe ($z_\dagger \sim 1.7$), as originally conjectured in the context of graduated dark energy (gDE). The talk will begin with a concise review of $\Lambda_{\rm s}$CDM cosmology, followed by a presentation of recent theoretical and observational developments that highlight its potential role as a candidate framework guiding the search for a renewed concordance cosmology.
