Supermassive black hole scalarization and effective field theory

TL;DR

This paper investigates the possibility of supermassive black hole scalarization within effective field theories and multi-scalar models, finding limitations in existing approaches to produce mass-dependent scalarization.

Contribution

It demonstrates that simple EFTs from integrating out heavy scalars cannot produce the desired supermassive black hole scalarization, and explores multi-scalar theories with limited success.

Findings

EFT from a heavy scalar does not yield correct coupling signs.

Single scalar theories do not produce mass-specific scalarization.

Multi-scalar theories can violate black hole uniqueness but not selectively for supermassive black holes.

Abstract

A model in which black hole scalarization occurs for supermassive black holes, while their less massive counterparts remain unscalarized, has been recently proposed. We explore whether this model can emerge from an effective field theory obtained by integrating out a heavy second scalar field. We show that the resulting EFT does not have the right coupling sign or the right hierarchy of scales. We then consider whether supermassive black hole scalarization could occur in theories with two scalars. We show that, although they can violate black hole uniqueness through curvature- and spin-induced scalarization, they do not naturally produce scalarization exclusively for supermassive black holes.