Saved in:
Bibliographic Details
Main Authors: Bedroya, Alek, Vafa, Cumrun, Wu, David H.
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2403.18005
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866929456754458624
author Bedroya, Alek
Vafa, Cumrun
Wu, David H.
author_facet Bedroya, Alek
Vafa, Cumrun
Wu, David H.
contents Quantum gravity (QG) has a natural cutoff given by the Planck scale $M_{\rm pl}$. However, it is known that the EFT of gravity can break down at a lower scale, the species scale $Λ_s\lesssim M_{\rm pl}$, if there are light species of particles. Here we point out that there is a third scale $Λ_{\rm BH}\lesssim Λ_s\lesssim M_{\rm pl}$, which marks the inverse length (or the temperature) of the smallest black hole where the EFT gives a correct description of its entropy and free energy. This latter scale is hard to detect from the viewpoint of EFT as it represents a phase transition to a state with lower free energy. We illustrate this using examples drawn from consistent QG landscape. In particular $Λ_{\rm BH}$ gets related to Gregory--Laflamme transition in the decompactification limits of quantum gravity and to the Horowitz--Polchinski solution in the light perturbative string limits. We propose the existence of $Λ_{\rm BH}$ marking the temperature at which neutral black holes undergo a phase transition, as a new Swampland condition for all consistent quantum theories of gravity. In the asymptotic regimes of field space $Λ_{\rm BH}$ is close to the mass scale of the lightest tower but deviates from it as we move inwards in the moduli space.
format Preprint
id arxiv_https___arxiv_org_abs_2403_18005
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Tale of Three Scales: the Planck, the Species, and the Black Hole Scales
Bedroya, Alek
Vafa, Cumrun
Wu, David H.
High Energy Physics - Theory
Quantum gravity (QG) has a natural cutoff given by the Planck scale $M_{\rm pl}$. However, it is known that the EFT of gravity can break down at a lower scale, the species scale $Λ_s\lesssim M_{\rm pl}$, if there are light species of particles. Here we point out that there is a third scale $Λ_{\rm BH}\lesssim Λ_s\lesssim M_{\rm pl}$, which marks the inverse length (or the temperature) of the smallest black hole where the EFT gives a correct description of its entropy and free energy. This latter scale is hard to detect from the viewpoint of EFT as it represents a phase transition to a state with lower free energy. We illustrate this using examples drawn from consistent QG landscape. In particular $Λ_{\rm BH}$ gets related to Gregory--Laflamme transition in the decompactification limits of quantum gravity and to the Horowitz--Polchinski solution in the light perturbative string limits. We propose the existence of $Λ_{\rm BH}$ marking the temperature at which neutral black holes undergo a phase transition, as a new Swampland condition for all consistent quantum theories of gravity. In the asymptotic regimes of field space $Λ_{\rm BH}$ is close to the mass scale of the lightest tower but deviates from it as we move inwards in the moduli space.
title The Tale of Three Scales: the Planck, the Species, and the Black Hole Scales
topic High Energy Physics - Theory
url https://arxiv.org/abs/2403.18005