The tale of three scales in quantum gravity | BlMSA-Tsinghua String Seminar

Abstract

Quantum gravity has a natural cutoff given by the Planck scale. However, the EFT of quantumgravity can break down at a lower scale known as the species scale, which is when highercurvature corrections become important. Additionally, there is a third scale which marks the inverselength (or the temperature) of the smallest black hole where the EFT gives a correct description ofits entropy and free energy. Understanding the distinction and interplay among these three scalescan shed light on fundamental aspects of guantum gravity and have important applications tophenomenology. In this talk, l will introduce the species scale as a moduli-dependent guantity insupersymmetric theories and motivate the existence of the black hole scale in quantum gravity. Atlast, l will provide evidence for two global bounds of the species scale and the black holes scaleover the moduli space of quantum gravity.