Gravitational Wave Resonance in Ultra-Light Dark Matter Halos

TL;DR

This paper explores how oscillating gravitational potentials from ultra-light dark matter halos can resonantly amplify gravitational waves, with potential significance in dense dark matter environments and specific resonance conditions.

Contribution

It demonstrates the interaction between ULDM-induced potentials and gravitational waves, highlighting conditions for resonance and potential amplification effects.

Findings

Resonance effects are negligible in the solar region.

Denser dark matter environments may enhance gravitational wave amplification.

Resonance frequency matches the ULA mass in the first resonance band.

Abstract

Ultra-Light Dark Matter (ULDM) halos constituted by Ultra-Light Axions (ULAs) generate gravitational potentials that oscillate in time. In this paper I show these potentials interact with gravitational waves, resonantly amplifying them. For all ULA masses considered, the resonance in the solar region is currently negligible, while in a denser dark matter environment, which may arise in different scenarios, it might become significant. The frequency of the amplified gravitational wave is equal to the ULA mass in the case of first resonance band, which represents the most efficient scenario.