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arXiv · 2609.27920

On the Modes at the Schwarzschild Black Hole Horizon

Dimitrios Giataganas·Alex Kehagias·Antonio Riotto
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Abstract

We discuss the origin of the modes appearing at the Schwarzschild black hole horizon and decaying at integer multiples of the surface gravity. We argue that no excitations generated at the horizon by the plunging of a particle into a black hole can leave it. Our argument is based on the fact that, when the particle approaches the horizon, its speed is necessarily boosted to ultra-relativistic values and its near-horizon gravitational field becomes a Dray-'t Hooft shockwave, which is an exact, nonanalytic, and nonperturbative solution of Einstein's equations. The corresponding metric perturbations are localized at the horizon and can never reach a distant observer.

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Dimitrios Giataganas, Alex Kehagias, Antonio Riotto. 2026-08-22. On the Modes at the Schwarzschild Black Hole Horizon. https://arxiv.org/abs/2609.27920

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