Effective action of a five-dimensional domain wall

TL;DR

This paper derives the low-energy effective action for perturbations of a five-dimensional two-scalar domain wall, revealing an additional scalar-curvature coupling affecting branon dynamics.

Contribution

It introduces a novel coupling between the light scalar and branon modes in the effective action, extending previous models of domain wall perturbations.

Findings

Identifies an extra scalar-curvature interaction in the effective action.

Shows the coupling influences branon physics and potential phenomenology.

Compares the effective action to the Nambu-Goto action, highlighting differences.

Abstract

We calculate the four-dimensional low-energy effective action for the perturbations of a two-scalar domain wall model in five dimensions. Comparison of the effective action to the Nambu-Goto action reveals the presence of an additional coupling between the light scalar field and the massless translation mode (branon excitation), which can be written in terms of the curvature scalar of the induced metric. We comment on the impact of this interaction to branon physics.