The fate of Newton's law in brane-world scenarios

TL;DR

This paper explores how string theory effects in brane-world scenarios can lead to observable deviations from Newton's law, including violations of the equivalence principle, due to D-brane backreaction and stringy corrections.

Contribution

It demonstrates that D-brane backreaction significantly alters the effective length of open strings, leading to detectable modifications in gravitational interactions at large distances.

Findings

Open string length increases due to D-brane backreaction.

Newtonian potential receives non-mass-proportional 1/r correction.

Stringy effects are screened at high temperatures.

Abstract

We consider brane-world scenarios embedded into string theory. We find that the D-brane backreaction induces a large increase in the open string's proper length. Consequently the stringy nature of elementary particles can be detected at distances much larger than the fundamental string scale. As an example, we compute the gravitational potential between two open strings ending on backreacting D3-branes in four-dimensional compactifications of type II string theory. We find that the Newtonian potential receives a correction that goes like 1/r but that is not proportional to the inertial masses of the open strings, implying a violation of the equivalence principle in the effective gravitational theory. This stringy correction is screened by thermal effects when the distance between the strings is greater than the inverse temperature. This suggests new experimental tests for many phenomenological models in type II string theory.