Induced Lorentz Violation on a Moving Braneworld

TL;DR

This paper investigates how a moving braneworld with compactified extra dimensions induces Lorentz-violating effects in the effective 4-D theory, due to bulk loop corrections, which can be described within the Standard Model Extension framework.

Contribution

It demonstrates that bulk loop effects in a moving braneworld generate UV-finite Lorentz-violating terms in the 4-D effective action, expanding understanding of Lorentz violation origins.

Findings

Bulk loops with non-zero winding produce Lorentz-violating terms.

These terms are UV-finite and compatible with the Standard Model Extension.

Lorentz violation arises from the global structure of the compactified extra dimension.

Abstract

We consider a braneworld scenario in which a flat 4-D brane, embedded in $M^{3,1} \times S^1$, is moving on or spiraling around the $S^1$. Although the induced metric on the brane is 4-D Minkowski, the would-be Lorentz symmetry of the brane is broken globally by the compactification. As recently pointed out this means causal bulk signals can propagate superluminally and even backwards in time according to brane observers. Here we consider the effective action on the brane induced by loops of bulk fields. We consider a variety of self-energy and vertex corrections due to bulk scalars and gravitons and show that bulk loops with non-zero winding generate UV-finite Lorentz-violating terms in the 4-D effective action. The results can be accommodated by the Standard Model Extension, a general framework for Lorentz-violating effective field theory.