6 papers
Inflationary Axion Isocurvature in the CMB across All Ultralight Masses
Rayne Liu, Wayne Hu, Daniel Grin
If the Peccei-Quinn symmetry of an ultralight axion is broken before the end of inflation, axion quantum fluctuations seed isocurvature perturbations, linking them to the tensor-to…
Phantom Mirage from Axion Dark Energy
Rayne Liu, Yijie Zhu, Wayne Hu +1
Supernova (SN) and baryon acoustic oscillation (BAO) distance measures have recently provided hints that the dark energy is not only dynamical but apparently evolves from normal to…
Warm and Fuzzy Dark Matter: Free Streaming of Wave Dark Matter
Rayne Liu, Wayne Hu, Huangyu Xiao
Wave or fuzzy dark matter that is produced with relativistic wavenumbers exhibits free streaming effects analogous to warm or hot particle dark matter with relativistic momenta. Ax…
Interference with Gravitational Instability: Hot and Fuzzy Dark Matter
Rayne Liu, Wayne Hu, Huangyu Xiao
Wave or fuzzy dark matter produced with high momenta behaves in many ways like hot particle dark matter while also possessing seemingly different phenomenology due to wave interfer…
Universal lower bound on the axion decay constant from free streaming effects
Keisuke Harigaya, Wayne Hu, Rayne Liu +1
We show that enhancement of the axion relic abundance compared to the standard misalignment contribution generically leads to the production of nonzero momentum axion modes, result…
Accurate method for ultralight axion CMB and matter power spectra
Rayne Liu, Wayne Hu, Daniel Grin
Ultralight axions (ULAs) with masses are well motivated in string-inspired models and can be part or all of the dark energy or the…