EFT Corrections to Majumdar-Papapetrou Black Holes

TL;DR

This work extends EFT analyses of near-horizon tidal deformations to a Majumdar-Papapetrou two-black-hole background, incorporating four-derivative corrections. It finds that in four dimensions the EFT corrections leave the tidal-scaling exponents $\lambda(j)$ unchanged, while in dimensions $D\ge5$ the exponents decrease, signaling stronger near-horizon tides, with explicit expressions derived up to $D\le10$. The authors develop a perturbative framework that preserves the MP structure, showing that metric corrections can be confined to the near-horizon $AdS_2$ throat (angle-dependent) while the transverse $S^{D-2}$ sector remains unaffected, and they provide a general formula for the corrected AdS$_2$ length scale, horizon radius, and scaling exponents across dimensions. They discuss the implications for EFT validity, arguing that the observed tidal enhancements relate to metric perturbation breakdown rather than a fundamental EFT cutoff, and outline avenues for exploring more complex multi-BH setups and nonlinear regimes.

Abstract

Recent studies on extremal black holes within effective field theories (EFT) of gravity have revealed an intriguing phenomenon: tidal forces near the horizon experience significant enhancement due to EFT corrections, potentially leading to a breakdown of the EFT framework. In this work, we investigate this effect in a two-black-hole Majumdar-Papapetrou spacetime modified by four-derivative EFT correction terms. Our analysis shows that while the scaling exponents, which measure the strength of the tidal forces near the horizon, remain unchanged under EFT corrections in $D=4$, they decrease for higher dimensions, enhancing the near-horizon tidal forces. We find an expression for the EFT corrections to the scaling exponents till $D \le 10$ and demonstrate that the metric corrections can be structured such that only the near-horizon $AdS_2$ throat undergoes angle-dependent modifications, while the transverse $S^{D-2}$ sector remains unaffected.