The conventional particle interpretation of cold dark matter (CDM) still lacks laboratory support and struggles to explain the basic properties of dwarf galaxies. This tension motivates wave dark matter (ψDM) composed of extremely light bosons ( m_ψ~10^-22 eV), which suppresses structure below the kpc scale by the uncertainty principle but retains the large-scale structure predicted by CDM. In the first part of this talk, I will present the first cosmological ψDM simulations that achieve an unprecedented high resolution capable of resolving dwarf galaxies. These simulations reveal that every ψDM halo has a prominent soliton core surrounded by fluctuating density granules. These predictions compare favorably with the observations of galaxy formation, the Lyman-alpha forest and reionization, and also help explain gravitational lensing flux anomalies.The second part of the talk focuses on GAMER, a GPU-accelerated adaptive mesh refinement (AMR) code. A rich set of physics modules is incorporated and which outperforms other widely-adopted AMR codes by one to two orders of magnitude. The code scales well to thousands of GPUs and achieves a uniform resolution as high as 10240³ cells. I will present several ongoing astrophysical projects with GAMER that require substantially higher resolution than previously feasible, including turbulence cascade in galaxy cluster mergers, star formation in isolated disk galaxies, supermassive black hole accretion, and ψDM simulations.

Dr. His-Yu Schive got his PhD in the Physics Department of National Taiwan University in 2012 and spent another 3 years as a postdoc there. Since 2016, he has been a postdoc in the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign. He is also a PI of the project "Ultra-high Resolution Astrophysical Simulations with GAMER" on the Blue Waters supercomputer. His research focuses on dark matter models, especially the wave dark matter, and high performance computing in astrophysics.