Dynamical AdS strings across horizons

TL;DR

This paper studies the nonlinear dynamics of a fundamental string in anti-de Sitter space, revealing how strong perturbations cause the string to extend into the horizon, disconnecting the quark-antiquark pair in the dual gauge theory.

Contribution

It demonstrates the dynamical formation of horizons on the string worldsheet and the transition to disconnected strings under strong perturbations, providing new insights into holographic flux tube behavior.

Findings

Strong perturbations cause the string to plunge into the horizon.

Effective horizons form dynamically on the string worldsheet.

The string transitions to two disconnected straight strings.

Abstract

We examine the nonlinear classical dynamics of a fundamental string in anti-de Sitter spacetime. The string is dual to the flux tube between an external quark-antiquark pair in $\mathcal{N}=4$ super Yang-Mills theory. We perturb the string by shaking the endpoints and compute its time evolution numerically. We find that with sufficiently strong perturbations the string continues extending and plunges into the Poincar\'e horizon. In the evolution, effective horizons are also dynamically created on the string worldsheet. The quark and antiquark are thus causally disconnected, and the string transitions to two straight strings. The forces acting on the endpoints vanish with a power law whose slope depends on the perturbations. The condition for this transition to occur is that energy injection exceeds the static energy between the quark-antiquark pair.