A Problem With delta-functions: Stress-Energy Constraints on Bulk-Brane Matching (with comments on arXiv:1508.01124)

TL;DR

This paper critically examines the use of delta-functions in modeling higher-codimension branes' back-reaction, clarifying stress-energy constraints and their implications for extra-dimensional cosmology.

Contribution

It provides a critical assessment of delta-function methods and clarifies stress-energy relations for branes, addressing misconceptions in recent literature.

Findings

Delta-function approach has limitations in higher codimension branes.

Stress-energy components are constrained by brane tension and off-brane relations.

Implications for cosmological constant problems in extra dimensions.

Abstract

We critically assess a recent assertion (arXiv:1508.01124) concerning using delta-functions to analyze how higher-codimension branes back-react on their environment. We also briefly summarize the state of the art: describing how stress-energy balance dictates the components of off-brane stress energy in terms brane tension; how this can modify the standard tension/defect-angle relation for codimension-two sources when dilatons are present; and how it all relates to extra-dimensional searches for a small cosmological constant.