Multifield ultralight dark matter
- Author(s)
- Mateja Gosenca, Andrew Eberhardt, Yourong Wang, Benedikt Eggemeier, Emily Kendall, J. Luna Zagorac, Richard Easther
- Abstract
Ultralight dark matter (ULDM) is usually taken to be a single scalar field. Here we explore the possibility that ULDM consists of N light scalar fields with only gravitational interactions. This configuration is more consistent with the underlying particle physics motivations for these scenarios than a single ultralight field. ULDM halos have a characteristic granular structure that increases stellar velocity dispersion and can be used as observational constraints on ULDM models. In multifield simulations, we find that inside a halo the amplitude of the total density fluctuations decreases as 1/N and that the fields do not become significantly correlated over cosmological timescales. Smoother halos heat stellar orbits less efficiently, reducing the velocity dispersion relative to the single field case and thus weakening the observational constraints on the field mass. Analytically, we show that for N equal-mass fields with mass m the ULDM contribution to the stellar velocity dispersion scales as 1/(Nm3). Lighter fields heat the most efficiently and if the smallest mass mL is significantly below the other field masses the dispersion scales as 1/(N2mL3).
- Organisation(s)
- Gravitational Physics
- External organisation(s)
- Stanford University, Kavli Institute for Particle Astrophysics and Cosmology, University of Auckland, Georg-August-Universität Göttingen, Yale University, Perimeter Institute for Theoretical Physics, Stanford Linear Accelerator Center
- Journal
- Physical Review D
- Volume
- 107
- No. of pages
- 11
- ISSN
- 2470-0010
- DOI
- https://doi.org/10.48550/arXiv.2301.07114
- Publication date
- 04-2023
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103012 High energy physics
- ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/multifield-ultralight-dark-matter(ed90a591-3d5c-49dd-aef4-417512b86e95).html