Over-Rotating Supertube Backgrounds

TL;DR

This paper investigates supertube probes in over-rotating supergravity backgrounds with closed timelike curves, demonstrating their stability and the existence of closed geodesics despite negative kinetic terms.

Contribution

It reveals the stability of BPS supertube probes and the presence of closed geodesics in over-rotating backgrounds with closed timelike curves.

Findings

BPS probes remain stable despite negative kinetic terms

Closed geodesics exist in these backgrounds

Probes exhibit radial oscillations indicating stability

Abstract

We study classical supertube probes on supergravity backgrounds which are sourced by over-rotating supertubes, and which therefore contain closed timelike curves. We show that the BPS probes are stable despite the appearance of negative kinetic terms in the probe action. By studying the radial oscillations of these probes, we show that closed geodesics exist on these backgrounds.