Speaker
Description
The ultralight dark matter (ULDM) model (also known as fuzzy dark matter or Bose-Einstein condensate dark matter) is one of alternatives to the cold dark matter (CDM) paradigm. It suggests that the dark matter particles are ultralight bosons with a tiny mass order of $10^{-22}$ eV, so that their de Broglie wavelength is of kiloparsec scale, that helps to resolve CDM tensions on the small scales. We consider ultralight scalar bosons condensate with $\psi^6$ self-interaction, which has a noticeable effect on the dark matter density distribution in highly dense regions, such as a central core of galactic dark matter halo or overlap of dark matter halo during the galaxies collision. At the same time, a contribution of tree-particles interaction is negligible in an outer part of the galactic dark matter halo and intergalactic medium. Thus all ULDM predictions on the large scales remain valid for the $\psi^6$ model, which, in turn, coincide with CDM predictions on these scales and are in agreement with observations. From the detailed analysis of thermodynamic characteristics of ULDM with $\psi^6$ self-interaction, we find the existence of two phases of dark matter separated by instability region in the (high density) core of dark matter halo.
