Presenter:  Prof. Bhupal Dev (Washington U., St. Louis)

Abstract: A dark matter (DM) halo intervening along the line of sight of a gravitational wave (GW) signal could induce a change in the speed of GW. We show that this change of speed is observable with the current LIGO sensitivity for a class of ultralight DM models which could form a Bose-Einstein condensate (BEC) in the early universe and behave as a single coherent wave instead of individual particles in galaxies. Hence, we propose to use the deviation in the speed of GW as a new probe of the BEC DM parameter space. With a multi-messenger approach to GW astronomy and/or with extended sensitivity to lower GW frequencies, the entire BEC DM parameter space can be effectively probed by our new method in the near future.

To see a video recording of the session: http://reunion.uv.es/p4oq7dyb8sb/