Delaying the Inevitable: Tidal Disruption in Microstate Geometries

TL;DR

This paper investigates tidal effects in microstate geometries that replace black hole horizons, revealing that large tidal deformations occur far from the structure, challenging the notion of smooth horizonless alternatives.

Contribution

It demonstrates that large tidal effects are inherent in microstate geometries and explores methods to mitigate these effects through bubble arrangements.

Findings

Large tidal deformations occur far from microstructure.

Bubble configurations can reduce certain gravitational multipoles.

Tidal effects remain significant at large distances from microstates.

Abstract

Microstate geometries in string theory replace the black-hole horizon with a smooth geometric "cap" at the horizon scale. In geometries constructed using superstratum technology, this cap has the somewhat surprising property that induces very large tidal deformations on infalling observers that are far away from it. We find that this large-distance amplification of the tidal effects is also present in horizonless microstate geometries constructed as bubbling solutions, but can be tamed by suitably arranging the bubbles to reduce the strength of some of the gravitational multipole moments. However, despite this taming, these tidal effects still become large at a significant distance from the microstructure. This result suggests that an observer will not fall unharmed into the structure replacing the black hole horizon.