2022-10-24 Seminar Report

In her talk, Dr. Elisa Ferreira exploited some of the intriguing models of dark matter (DM), one of the biggest mysteries in cosmology. While there are many different models to explain the nature of this elusive component, she presented a class of dark matter models: ultra-light dark matter (ULDM) or ultra-light axions (ULA). She explained that one of the most interesting features of this class of DM models is that it might condense in the interior of the halos of galaxies forming a Bose-Einstein condensate or superfluid. This interesting quantum phenomena on macroscopic scales, and the wave nature of ULDM leads to different and interesting astrophysical consequences that can be probed on small scales. She first reviewed the fuzzy dark matter model, one of the most well studied ULA models, and then introduced the DM superfluid model. Upon condensation in the interior of galaxies, DM dynamics in this model can represent that of so-called modified Newtonian dynamics on galactic scales. Dr. Ferreira showed the theoretical description of this model and its interesting phenomenology, especially on small scales.

Reported by Ryo Namba

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