Speaker
Description
Ultralight cold dark matter, also known as fuzzy dark matter or ultralight axion, is a scalar field with an extremely light mass of approximately 10^{-22} eV. In this model, dark matter in galactic halos exists in a Bose-Einstein condensate state and is described by a macroscopic wave function with a de Broglie wavelength on the order of a kiloparsec. This approach offers potential solutions to small-scale issues in the cold dark matter (CDM) paradigm and may help explain several cosmological mysteries, such as galaxy sizes and masses, the satellite galaxy plane, the Hubble tension, and the final parsec problem. If the scalar field attains a field value at the grand unified theory (GUT) scale, it can account for the observed dark matter density. In models with interactions, the field could be a pseudo Nambu-Goldstone boson associated with the GUT phase transition, which may also yield insights into the mass of neutrinos and the electroweak interaction scale.
