Kavli Affiliate: Wayne Hu
| First 5 Authors: Christian Capanelli, Wayne Hu, Evan McDonough, ,
| Summary:
In the Fuzzy Dark Matter (FDM) scenario, the dark matter is composed of an
ultra-light scalar field with coherence length and wave interference on
astrophysical scales. Scalar fields generically have quartic self-interactions
that modify their dispersion relation and the associated evolution of density
perturbations. We perform the first dedicated analysis of the role of wave
interference on this evolution due to self-interactions in FDM and vice versa,
developing a perturbative treatment applicable at early times and then
comparing against a suite of fully nonlinear benchmark simulations, varying the
dark matter density, interaction strength, and fiducial momentum scale. We
explicitly simulate the limit where this momentum scale is relatively high
compared with the scale of the simulation volume, applicable to cases where the
dark matter is initially “warm" due to causal constraints on a
post-inflationary production or in virialized halos and other “thermalized"
cases with initially cold production. We find that in such scenarios, density
perturbations are unable to grow on the expected self interaction time scale
because of interference effects, instead saturating on the much shorter de
Broglie crossing time, with a dependence on the sign of the interaction.
Finally, we comment on the implications of our results for astrophysical
systems such as high-density ultra-faint dwarf galaxies where wave interference
plays an important role.
| Search Query: ArXiv Query: search_query=au:”Wayne Hu”&id_list=&start=0&max_results=3