Radion Stabilization by Brane Matter

TL;DR

This paper presents a static five-dimensional solution with brane matter that influences the size of the extra dimension and affects the propagation speeds of fields, highlighting the role of matter in radion stabilization.

Contribution

It introduces a new static solution to Einstein's equations with brane matter, showing how matter content stabilizes the extra dimension's radius.

Findings

The radius of the fifth dimension depends on brane matter content.

Propagation speeds of bulk and brane fields vary with the fifth coordinate.

The solution incorporates matter density, pressure, and tension on the branes.

Abstract

We find a static solution to Einstein's field equations on a five-dimensional orbifold with a compact S_1/Z_2 fifth direction and Poincare invariant 3+1 sections. The solution describes a theory with bulk cosmological constant and 3-branes at the orbifold fixed points which carry matter density and pressure in addition to tension. The radius of the fifth dimension is determined by the matter content of the branes. The ratio of the space and time components of the metric depends on the fifth coordinate. Thus, the speed of propagation of massless fields is path dependent. For example, bulk and brane fields propagate with different speeds.