Swampland conjectures for type IIB orientifolds with closed-string U(1)s

TL;DR

This paper investigates the applicability of swampland conjectures to type IIB orientifold compactifications with closed-string U(1) gauge fields, revealing differences from $ =2$ cases and highlighting stability and emergence ambiguities.

Contribution

It extends swampland conjecture analysis to $ =1$ orientifold compactifications with closed-string U(1)s, identifying new challenges and differences from $ =2$ scenarios.

Findings

Certain structures from $ =2$ compactifications are absent in $ =1$ cases.

Stability assumptions need to be relaxed in $ =1$ orientifolds.

Ambiguities arise in the emergence of gauge symmetries for the $h^{2,1}_+$ sector.

Abstract

We study the weak gravity conjecture, the swampland distance conjecture and the emergence proposal for $\mathcal{N}=1$ orientifold compactifications of type IIB string theory with O3-/O7-planes. We allow for orientifold projections with $h^{2,1}_+\neq 0$ which gives rise to closed-string $U(1)$ gauge fields, and our findings show that certain structures present for $\mathcal N=2$ compactifications are not present for $\mathcal N=1$. In particular, assumptions about stability have to be relaxed and we encounter an ambiguity for the emergence of gauge symmetries associated with the $h^{2,1}_+$ sector.