Wave-envelope dark matter beyond the monochromatic paradigm

TL;DR

This paper introduces wave-envelope dark matter, a new paradigm where field mixing causes slow modulation and sideband features in signals, challenging the traditional monochromatic assumption in ultralight dark matter searches.

Contribution

It demonstrates that mixing of ultralight wave dark matter fields induces a parametric structure, leading to wave-envelope phenomena with distinctive spectral features.

Findings

Field mixing causes slow modulation in dark matter signals.

Wave-envelope structure results in characteristic sidebands.

Implications discussed for neutrino observables.

Abstract

Ultralight dark matter searches widely assume that signals are monochromatic, with a single frequency set by the mass. This assumption is generally violated in the presence of field mixing, even when the constituent fields have similar frequencies. Instead, dark matter signals can exhibit a two-timescale structure with intrinsic slow modulation. We demonstrate that mixing between ultralight wave dark matter fields induces a parametric structure, leading to a scenario we refer to as wave-envelope dark matter, in which a slow-beating envelope emerges alongside the primary oscillation. This results in distinctive features such as slow modulation and characteristic sideband structures in the frequency spectrum, beyond the conventional monochromatic expectation. As a representative example, we briefly discuss implications for neutrino observables.