Swampland Constraints on 5d $\mathcal{N}=1$ Supergravity

Understand

We propose Swampland constraints on consistent 5-dimensional ${\cal N}=1$ supergravity theories.

• We focus on a special class of BPS magnetic monopole strings which arise in gravitational theories.
• The central charges and the levels of current algebras of 2d CFTs on these strings can be calculated by anomaly inflow mechanism and used to provide constraints on the low-energy particle spectrum and the effective action of the 5d supergravity based on unitarity of the worldsheet CFT.
• In M-theory, where these theories are realized by compactification on Calabi-Yau 3-folds, the special monopole strings arise from wrapped M5-branes on special ("semi-ample") 4-cycles in the threefold.