EFT Corrections to Charged Black Hole Quasinormal Modes

TL;DR

This paper investigates how higher-derivative Effective Field Theory corrections affect the quasinormal modes of Reissner-Nordstr"om black holes, especially near extremality, and tests a recent causality bound using Standard Model effects.

Contribution

It derives a corrected quasinormal mode equation for charged black holes and tests the causality bound with Standard Model contributions, providing new insights into EFT and black hole dynamics.

Findings

EFT corrections modify quasinormal mode frequencies near extremality.

The causality bound is verified with Standard Model effects.

Results enhance understanding of EFT, black hole extremal behavior, and causality constraints.

Abstract

We study the impact of higher-derivative corrections from Effective Field Theory on the quasinormal mode spectrum of Reissner-Nordstr\"om black holes. While previous work has explored corrections to Schwarzschild and Kerr black holes - typically using small-rotation approximations - a comprehensive analysis near extremality remains lacking. We focus on Reissner-Nordstr\"om black holes as a tractable model admitting an extremal limit, enabling investigation of the effect of these corrections on the so-called zero damped modes, which dominate in this regime. Specifically, we derive a corrected Moncrief equation governing quasinormal modes and present both analytic and numerical results for the corrected frequencies. This work also offers the first explicit test of the recently proposed "Quasinormal Mode Causality" bound arXiv:2401.05524, which constrains Effective Field Theory coefficients by requiring that quasinormal mode lifetimes do not increase measurably under ultraviolet-complete Effective Field Theory corrections. Using Standard Model contributions - particularly those arising from integrating out the electron - we verify that this bound holds. Our results provide new insights into the interplay between Effective Field Theory, extremal black hole dynamics, and causality in gravitational theories.