Ultralight Dark Matter from the Edge of Field Space
High Energy Physics - Phenomenology
2026-05-27 v3 Cosmology and Nongalactic Astrophysics
Abstract
We introduce a novel class of bosonic dark matter candidates that we dub wallions, featuring boundaries in field space. The wallion mass is exponentially suppressed when the separation between boundaries far exceeds their intrinsic width and remains radiatively stable under self-interactions. We study the early-universe evolution of wallions and the associated cosmological signatures. Finally, we show that instanton effects can dynamically generate field-space boundaries and discuss possible experimental probes once the wallion couples to Standard Model fields.
Cite
@article{arxiv.2511.09622,
title = {Ultralight Dark Matter from the Edge of Field Space},
author = {Mathias Becker and Francesco D'Eramo and Ville Vaskonen},
journal= {arXiv preprint arXiv:2511.09622},
year = {2026}
}
Comments
6 pages, 3 figures, version published in Physical Review Letters