On Witten's Instability and Winding Tachyons

TL;DR

This paper examines the potential role of winding tachyons in the decay of Kaluza-Klein spacetimes via black string instabilities, analyzing classical configurations and energetics from a spacetime perspective.

Contribution

It provides a spacetime analysis of black string decay mechanisms, exploring the influence of winding tachyons on tunneling barriers and decay rates.

Findings

Winding tachyons do not appear to enhance decay at large compactification radii.

Classical configurations interpolating between flat space and bubbles are identified.

The effects of tachyons at string-scale radii remain inconclusive due to theoretical limitations.

Abstract

We investigate, from a spacetime perspective, some aspects of Horowitz's recent conjecture that black strings may catalyze the decay of Kaluza-Klein spacetimes into a bubble of nothing. We identify classical configurations that interpolate between flat space and the bubble, and discuss the energetics of the transition. We investigate the effects of winding tachyons on the size and shape of the barrier and find no evidence at large compactification radius that tachyons enhance the tunneling rate. For the interesting radii, of order the string scale, the question is difficult to answer due to the failure of the $\alpha^\prime$ expansion.