The influence of D-branes' backreaction upon gravitational interactions between open strings

TL;DR

This paper investigates how the backreaction of D3-branes influences gravitational interactions between open strings, revealing a potential energy that can deviate from Newtonian gravity and violate the equivalence principle under certain conditions.

Contribution

It provides a detailed analysis of the gravitational backreaction of open strings on D3-branes in AdS5 backgrounds, highlighting effects unique to string theory.

Findings

Gravitational potential between open strings scales as 1/r at large distances.

Backreaction can induce corrections to Newtonian gravity that violate the equivalence principle.

Enhanced gravitational attraction is specific to string theory and not observed for point particles.

Abstract

We argue that gravitational interactions between open strings ending on D3-branes are largely shaped by the D3-branes' backreaction. To this end we consider classical open strings coupled to general relativity in Poincare AdS5 backgrounds. We compute the linear gravitational backreaction of a static string extending up to the Poincare horizon, and deduce the potential energy between two such strings. If spacetime is non-compact, we find that the gravitational potential energy between parallel open strings is independent of the strings' inertial masses and goes like 1/r at large distance r. If the space transverse to the D3-branes is suitably compactified, a collective mode of the graviton propagates usual four-dimensional gravity. In that case the backreaction of the D3-branes induces a correction to the Newtonian potential energy that violates the equivalence principle. The observed enhancement of the gravitational attraction is specific to string theory; there is no similar effect for point-particles.