The page curve and baby universes

Black hole thermodynamics suggests that in order to describe the physics of distant observers, one may model a black hole as a standard quantum system with a density of states set by the Bekenstein-Hawking entropy S-BH. This idea has long been considered to be in strong tension with Hawking's prediction that radiation from black holes is nearly thermal, and with low-energy gravity more generally. But the past two years have shown that low-energy gravity does offer a self-consistent description of black hole evaporation consistent with the above idea, and which in particular reproduces the famous Page curve. We provide a brief overview of this new paradigm, focusing on Lorentz-signature asymptotically-flat spacetimes and emphasizing operationally defined observables that probe the entropy of Hawking radiation.

Automated summary

The new paradigm in black hole thermodynamics suggests modeling black holes as standard quantum systems with a density of states set by Bekenstein-Hawking entropy. Recent research has shown that low-energy gravity offers a consistent description of black hole evaporation, reproducing the Page curve. This paradigm focuses on asymptotically-flat spacetimes and emphasizes observables that probe the entropy of Hawking radiation.