Dynamical Tadpoles and Weak Gravity Constraints

TL;DR

This paper explores how dynamical tadpoles in non-supersymmetric string models can violate swampland constraints, with implications for consistency conditions and dualities in string theory and quantum gravity.

Contribution

It demonstrates that dynamical tadpoles can lead to swampland violations and derives a new consistency condition related to tadpole cancellation in string models.

Findings

Dynamical tadpoles can violate the axion Weak Gravity Conjecture.

Cancellation of dynamical tadpoles imposes new consistency conditions.

Re-derivation of Z-minimization criterion for AdS vacua.

Abstract

Non-supersymmetric string models are plagued with tadpoles for dynamical fields, which signal uncanceled forces sourced by the vacuum. We argue that in certain cases, uncanceled dynamical tadpoles can lead to inconsistencies with quantum gravity, via violation of swampland constraints. We describe an explicit realization in a supersymmetric toroidal ${\textbf{Z}}_2\times{\textbf{Z}}_2$ orientifold with D7-branes, where the dynamical tadpole generated by displacement of the D7-branes off its minimum leads to violation of the axion Weak Gravity Conjecture. In these examples, cancellation of dynamical tadpoles provides consistency conditions for the configuration, of dynamical nature (as opposed to the topological conditions of topological tadpoles, such as RR tadpole cancellation in compact spaces). We show that this approach provides a re-derivation of the Z-minimization criterion for AdS vacua giving the gravitational dual of a-maximization in 4d $\mathcal{N}=1$ toric quiver SCFTs.