The consistency of codimension-2 braneworlds and their cosmology

Understand

We study axially symmetric codimension-2 cosmology for a distributional braneworld fueled by a localised 4D perfect fluid, in a 6D Lovelock theory.

• We argue that only the matching conditions (dubbed topological) where the extrinsic curvature on the brane has no jump describe a pure codimension-2 brane.
• If there is discontinuity in the extrinsic curvature on the brane, this induces inevitably codimension-1 distributional terms.
• We study these topological matching conditions, together with constraints from the bulk equations evaluated at the brane position, for two cases of regularisation of the codimension-2 defect.