Cosmologies, singularities and quantum extremal surfaces

Cosmologies, singularities and quantum extremal surfaces

Blog Article

Abstract Following [1], we study quantum extremal surfaces in various families of cosmologies with Big-Crunch singularities, by extremizing the generalized entropy in 2-dimensional backgrounds which can be thought of as arising from dimensional reduction.Focussing first on the isotropic AdS Kasner case, introducing a spatial regulator enables relating the locations in time of the quantum extremal surface and the observer.This shows that 30x24x24 wall cabinet the quantum extremal surface lags behind the observer location.

A potential island-like region, upon analysing more closely near the island boundary, turns out to be inconsistent.Similar results arise for other holographic cosmologies.We then study certain families of null Kasner singularities where we find that the quantum extremal surface can reach the near singularity region although the on-shell generalized entropy is generically singular.

We also study other cosmologies including de earthbath facial wipes Sitter (Poincare slicing) and FRW cosmologies under certain conditions.