String Spreading on Black Hole Horizon

TL;DR

This paper investigates string spreading on a Schwarzschild black hole horizon, demonstrating angular spreading that covers the horizon and radial suppression due to Lorentz contraction, using an exact curved background analysis.

Contribution

It provides an exact curved spacetime analysis of string spreading on a black hole horizon, extending prior approximate or heuristic studies.

Findings

String spreads angularly to cover the horizon

Radial spreading is suppressed by Lorentz contraction

Spreading occurs within fixed finite resolution time

Abstract

The phenomenon of string spreading on the black hole horizon, as originally discussed by Susskind, is considered in the {\it exact} curved Schwarzschild background. We consider an oscillating string encircling the black hole and contracting towards the horizon. We then compute the angular and radial spreading of the string, as seen by a static observer at spatial infinity using fixed finite resolution time. Within our case study we find that there is indeed a spreading of the string in the angular direction, such that the string eventually covers the whole horizon. However, regarding the radial direction, we find that Lorentz-contraction suppresses the radial string spreading.