A new scale in the sky

TL;DR

This paper explores a potential astrophysical signature of a new ultraviolet scale in theories with gravity and gauge fields, which could help differentiate viable theories from the swampland.

Contribution

It proposes a phenomenological signature of the ultraviolet scale in electromagnetic observations, linking theoretical conjectures to observable astrophysical phenomena.

Findings

Identification of a possible astrophysical signature of the ultraviolet scale

Connection between swampland criteria and electromagnetic observations

Potential for observational tests of quantum gravity conjectures

Abstract

The existence of a new ultraviolet scale $\Lambda=g M_P$ for effective theories with gravity and U(1) gauge fields has recently been conjectured as a possible criterion for distinguishing parts of the swampland from the string landscape. Here we discuss a possible phenomenological signature of this scale, for electromagnetic fields, in astrophysical observations.