Magnetic fields are observed on virtually all length scales of the modern Universe, from planets and stars to galaxies and galaxy clusters. Observations of blazars suggest that even the intergalactic medium is permeated by magnetic fields. Such large-scale fields were most likely generated shortly after the Big Bang and therefore are a unique window into the physics of the very early Universe.
In my seminar, I will review theoretical models of magnetogenesis and confront these with observational constraints. I will address the possible origin of magnetic fields in the early Universe, during inflation and the cosmological phase transitions, as well as their pre-recombination evolution in decaying magnetohydrodynamical (MHD) turbulence. In particular, I will discuss the results of high-resolution numerical simulations that show an efficient amplification of magnetic energy due to the so-called chiral anomaly, a standard model effect that necessarily leads to an extension of the MHD equations at high energies. Finally, I will discuss how magnetic fields produced by these chiral MHD dynamos can drive primordial gravitational waves.
Zoom link: https://cern.zoom.us/j/98399499159
Meeting ID: 983 994 99159
Passcode: 323288