The second cosmology seminar of the week takes place on Friday 24th of October, room E349 at 2:00pm. We will have the pleasure to listen to José Beltrán Jiménez from the Gravitation and Cosmology Group, University of Salamanca (Spain).
At 2:00pm, room E349, José Beltrán Jiménez will be talking about
Electromagnetically K-mouflaged dark matter and the ladder symmetries of screened objects
I will discuss a cosmological scenario where dark matter is provided with a dark electric charge with a dark electromagnetic sector featuring a screening mechanism so that all the effects only appear at low redshift, when dark matter is sufficiently clustered. Within these models, it is natural to have a universe described by a Lemaitre model instead of a FLRW. Instead of solving the full relativistic equations, I will consider a Newtonian approach that is sufficient for a matter dominated universe with, possibly, a cosmological constant. In this scenario, it is possible to explain the Hubble tension in terms of the dark electric repulsion between dark matter halos. After reviewing some phenomenological consequences, I will proceed to analysing the deformability of dark matter haloes due to the dark electromagnetic interaction and show the emergence of a curious 2-ladder structure connecting different multipoles for the case of Born-Infeld electromagnetism. Furthermore, some multipoles exhibit a vanishing polarisability or magnetisation, thus showing an intriguing resemblance with the vanishing of the Love numbers of black holes. Finally, I will explain how analogous results arise for the scalar DBI theories in arbitrary dimensions and some finite size effects.