AxioNyx 1.1

AxioNyx is a cosmological simulation code for Fuzzy/Ultralight Dark Matter (FDM/ULDM),
built as a fork of the Nyx hydrodynamics code developed at Lawrence Berkeley National Laboratory. It evolves the Schrödinger-Poisson equations on a uniform grid using a pseudospectral method, and on sub-regions a high-order finite-difference scheme. It supports mixed FDM+CDM cosmologies across cosmic scales, from structure formation, to halo morphology, to FDM soliton oscillations.

The codebase has been developed over several years by a number of researchers in the ultralight dark matter community.

AxioNyx 1.1 is a modernized public release, maintained by Yourong Wang, and accompanies the publication

Wang, Y. (2026). Lyman-α Forest Signatures of Mixed Fuzzy and Cold Dark Matter.
arXiv:2604.06038

The original AxioNyx paper (Schwabe et al. 2020, arXiv:2007.08256 / PRD 102.083518) describes
the foundational method. If you use AxioNyx in your research, please cite both the original paper and the version you used.