Power of Black Hole Physics: Seeing through the Vacuum Landscape

TL;DR

This paper extends the black hole bound on the number and masses of particle species to de Sitter and quasi‑de Sitter vacua and uses it to constrain the landscape of vacua, including slow‑roll inflationary states. By analyzing BH formation, evaporation, and horizon scales, it derives universal limits on how many species can exist for a given mass, how long vacua can last, and how inflationary dynamics are restricted. The results connect low‑energy perturbative data to high‑scale gravitational consistency, yielding bounds on the cosmological constant, flux vacua counts, and inflationary model parameters, and highlighting how a large landscape can force vacua to be more curved or shorter lived. The study emphasizes that the lowered gravitational cutoff with many species and the presence of domain walls or branes shape which vacua can be consistently realized within quantum gravity, with potential swampland implications.

Abstract

In this paper we generalize the black hole bound of arXiv:0706.2050 to de Sitter spaces, and apply it to various vacua in the landscape, with a special emphasis on slow-roll inflationary vacua. Non-trivial constraints on the lifetime and the Hubble expansion rate emerge. For example, the general tendency is, that for the fixed number and the increasing mass of the species, vacua must become more curved and more unstable, either classically or quantum mechanically. We also discuss the constraints on the lifetime of vacua in the landscape, due to decay into the neighboring states.