Résumé |
The weak gravity conjecture asserts that any consistent gauge
theory coupled to quantum gravity should exhibit so-called super-extremal
particles, i.e. states whose charge-to-mass ratio exceeds that of an
extremal black hole. On the other hand, a stronger variant of this
conjecture is the tower weak gravity conjecture, which predicts an
infinite tower of super-extremal states in every direction of the charge
lattice of the theory under consideration. This formulation ensures that
the weak gravity conjecture remains consistent under circle reduction of a
given theory. However, in string theory compactifications on Calabi-Yau
threefolds, there are instances where no tower of super-extremal particle
states appears to be present. To address this issue, I will discuss recent
developments in our understanding of the tower weak gravity conjecture
leading to the Minimal Weak Gravity Conjecture, which states that towers
of super-extremal particles occur if and only if they are required by
consistency of the weak gravity conjecture under dimensional reduction. |