Constraining interacting dark energy models with black hole superradiance

TL;DR

This paper proposes using black hole superradiance as a new astrophysical method to constrain interacting dark energy and dark matter models, complementing cosmological observations.

Contribution

It introduces a novel approach linking black hole superradiance to DE-DM interactions, providing independent constraints on these models.

Findings

Constraints on DE-DM coupling strength derived from black hole observations.

Superradiance can be affected by DE-DM interactions through effective mass modifications.

Current constraints are loose due to limited data, but the method offers a new probe for dark sector physics.

Abstract

The recent preference for a dynamical dark energy (DE) from the Dark Energy Spectroscopic Instrument seems to call for interactions between DE and dark matter (DM), either from direct DE-DM interaction or indirect interaction induced by modified gravity. Therefore, an independent probe for these kinds of DE-DM interactions would be appealing from observational aspects. In this paper, we propose the black hole superradiance as a novel astrophysical probe for field-theoretic interacting DE-DM models, providing complementary constraints independent of large-scale cosmological observations. The core principle is that the DE-DM interaction can alter the effective mass of the superradiant ultralight boson, thereby modifying its superradiant instability rate around spinning black holes. We explore this connection through two distinct scenarios: a model where the DE field mediates a dark fifth force within the DM sector, affecting the superradiance from DM particles; and a novel mechanism where the DE field itself becomes superradiant due to the effective mass enhancement induced by dense DM spikes around supermassive black holes. By applying a statistical framework to black hole observations in both scenarios, we derive constraints on the fundamental DE-DM coupling strength. Although the current constraints are rather loose due to small samples and inaccurate measurements, our work provides new astrophysical constraints on these interacting DE-DM scenarios and establishes a new synergy between black hole physics and cosmology for probing the fundamental nature of the dark sector.