Physics Beyond the Standard Model in Leptonic & Hadronic Processes and Relevant Computing Tools

Spherical Collapse and Sudden Singularities: Insights from the $\Lambda_{\rm s}$CDM Model

Not scheduled

20m

Amphitheater "Alkis Argyriades" ( University of Athens, Greece )

Research Talks of “Session 9”

Speaker

Evangelos Achilleas Paraskevas (University of Ioannina)

Description

The $\Lambda_{\mathrm{s}}$CDM model, which posits a rapid transition from anti-de Sitter (AdS) to de Sitter (dS) vacua around redshift $z_{\dagger} \approx 2$, aims to resolve cosmological tensions, including those related to $H_0$ and $S_8$. This study examines the impact of a type II singularity at $z = z_{\dagger}$ on the evolution of cosmic structures, specifically the generalization of the spherical collapse model to incorporate the sudden singularity. We analyze the matter overdensity, indicating deviations of the $\Lambda_{\mathrm{s}}$CDM model from the Planck-$\Lambda$CDM expectations. The observable effects of sudden singularities on virialized overdensities will be discussed.