Xavier Callens

The Frontier Triad: Swampland Distance Bounds, Tachyon Condensation, and Non-Perturbative Vacuum Decay on K3 × T²

Revision (2026-09-18): orientifold bookkeeping. The tadpole configuration is placed in the orientifold K3 × T²/Z2, with the 4 O7-planes at the fixed points of T²/Z2, and the charges are stated in units of μ7/4 (+1 and −4 in D7 units; Sen hep-th/9605150, Tripathy–Trivedi hep-th/03...