Supergravity Supertubes

TL;DR

This work constructs an exact IIA supergravity solution for a 1/4-BPS supertube, showing it reproduces the worldvolume data of D2-tubes with dissolved strings and D0-branes, including the radius, tension, and angular momentum. The solution exhibits a D2-dipole moment and, crucially, imposes a causality bound on angular momentum: $|J| \le |Q_s Q_0|/N$, with over-rotation triggering closed timelike curves and a ghost instability on D2 probes. The authors also demonstrate a no-force condition for multiple, parallel supertubes and verify stability via supersymmetric brane probes, thereby linking global spacetime causality to local worldvolume dynamics. They further discuss extensions to higher-dimensional and KK settings, suggesting a broader framework for SUSY rotating brane sources and their non-singular completions.

Abstract

We find the supergravity solution sourced by a supertube: a (1/4)-supersymmetric D0-charged IIA superstring that has been blown up to a cylindrical D2-brane by angular momentum. The supergravity solution captures all essential features of the supertube, including the D2-dipole moment and an upper bound on the angular momentum: violation of this bound implies the existence of closed timelike curves, with a consequent ghost-induced instability of supertube probes.