Love numbers of black p-branes: fine tuning, Love symmetries, and their geometrization

TL;DR

This paper investigates the scalar static response coefficients (Love numbers) of black p-branes in higher dimensions, revealing hidden symmetries called Love symmetries, and explores their geometric interpretation and behavior in extremal limits.

Contribution

It uncovers the presence of Love symmetries in black p-branes and explains their behavior and geometrization in various limits, extending understanding of black brane responses.

Findings

Love numbers of extremal p-branes are always zero.

Love symmetries act on perturbation equations and are not background isometries.

Geometrization of Love symmetries occurs only for p=0,1 in certain limits.

Abstract

We compute scalar static response coefficients (Love numbers) of non-dilatonic black $p$-brane solutions in higher dimensional supergravity. This calculation revels a fine-tuning behavior similar to that of higher dimensional black holes, which we explain by ``hidden'' near-zone Love symmetries. In general, these symmetries act on equations for perturbations but they are not background isometries. The Love symmetry of charged $p=0$ branes is described by the usual $SL(2,\mathbb{R})$ algebra. For $p=1$ the Love symmetry has an algebraic structure $SL(2,\mathbb{R})\times SL(2,\mathbb{R})$. The $p=0,1$ Love symmetries reduce to isometries of the near-horizon Schwarzschild-AdS$_{p+2}$ metric in the near-extremal finite temperature limit. They further reduce to the AdS$_{p+2}$ isometries in the extremal zero-temperature limit. We call this process geometrization. In contrast, for the $p>1$ cases, the Love symmetry is always an $SL(2,\mathbb{R})$, and there is no limit in which it becomes geometric. We interpret geometrization and its absence as a consequence of the local equivalence between the Schwarzschild-AdS$_{p+2}$ and pure AdS$_{p+2}$ spaces for $p=0,1$, which does not hold for $p>1$. We also show that the static Love numbers of extremal $p$-branes are always zero regardless of spacetime dimensionality, which contrasts starkly with the non-extremal case. Overall, our results suggest that the Love symmetry is hidden by nature, and it can acquire a geometric meaning only if the background has an AdS$_{2}$ or AdS$_{3}$ limit.