“KMI theory seminar” 25th Sep. (Mon)  14：00 –
Date: September 25th (Mon.) 14:00 – 16:00
Place: ES635
Speaker: Dr. Filippo Anzuini (University of Melbourne)
Title: Primordial magnetogenesis in multicomponent dark matter

Abstract: The existence of large-scale magnetic fields permeating galaxies, clusters of galaxies
and cosmic voids can be explained via the generation of magnetic field “seeds” in the Early Universe.
In this picture, magnetogenesis takes place in a system composed by the primordial plasma and dark matter, leading to a complex dynamics that requires a numerical approach.
Using lattice simulations, we show that the production of intense primordial magnetic fields is possible assuming that photons couple with axion-like particles (ALPs), QCD axions and dark photons. Once the Hubble parameter becomes smaller than the axion mass, the latter starts to oscillate, and part of its energy density is spent producing gauge fields.
While the energy density of dark photons becomes higher than the one of the axion, the high conductivity of the primordial plasma damps the oscillations of the photon field even for relatively large axion-photon couplings. However, the interaction between photons and dark photons leads to a much more efficient sourcing of electromagnetic fields, boosting the efficiency of the magnetic dynamo and allowing for a viable mechanism for the generation of intense primordial magnetic fields.

Please join the seminar!