Physical status of codimension-one infinite-distance ETW singularities

Determine whether dynamically generated codimension-one curvature singularities that drive scalar fields to infinite distance in field space should be interpreted as physical End-of-the-World brane cobordism defects within string theory, rather than as unphysical backgrounds.

Background

The paper studies codimension-one End-of-the-World (ETW) singularities that arise in dynamical cobordism scenarios and drive scalars to infinite distance in field space. While these configurations are motivated by the Cobordism Conjecture and appear in string theory, not every EFT singularity is necessarily physical.

The authors compare these singularities against several diagnostics (Gubser’s and Maldacena–Nuñez criteria) and propose a new geometric criterion, but emphasize the overarching uncertainty about whether such singularities should always be regarded as physical ETW branes.

References

It is thus unclear whether any dynamically generated co-dimension one singularity that explores infinite distance in field space should be read as a physical cobordism defect.

— End-of-the-World Singularities: The Good, the Bad, and the Heated-up  (2603.18133 - Calderón-Infante et al., 18 Mar 2026) in Introduction