Gravity in the Randall-Sundrum Brane World

TL;DR

This paper analyzes weak gravitational fields in the Randall-Sundrum brane-world, revealing linearized Brans-Dicke gravity behavior, shadow matter effects, and Kaluza-Klein corrections to the gravitational field.

Contribution

It provides a detailed linearized gravitational analysis in the Randall-Sundrum model, including shadow matter effects and corrections to Schwarzschild geometry.

Findings

Brans-Dicke parameters depend on brane tension and separation.

Shadow matter causes 25% weaker light deflection.

Kaluza-Klein corrections modify the gravitational field at large distances.

Abstract

We discuss the weak gravitational field created by isolated matter sources in the Randall-Sundrum brane-world. In the case of two branes of opposite tension, linearized Brans-Dicke (BD) gravity is recovered on either wall, with different BD parameters. On the wall with positive tension the BD parameter is larger than 3000 provided that the separation between walls is larger than 4 times the AdS radius. For the wall of negative tension, the BD parameter is always negative but greater than -3/2. In either case, shadow matter from the other wall gravitates upon us. For equal Newtonian mass, light deflection from shadow matter is 25 % weaker than from ordinary matter. Hence, the effective mass of a clustered object containing shadow dark matter would be underestimated if naively measured through its lensing effect. For the case of a single wall of positive tension, Einstein gravity is recovered on the wall to leading order, and if the source is stationary the field stays localized near the wall. We calculate the leading Kaluza-Klein corrections to the linearized gravitational field of a non-relativistic spherical object and find that the metric is different from the Schwarzschild solution at large distances. We believe that our linearized solution corresponds to the field far from the horizon after gravitational collapse of matter on the brane.