Baryon Asymmetry of Universe: View from Superfluid 3He

Abstract

The origin of the excess of matter over antimatter in our Universe remains one of the fundamental problems. The dynamical baryogenesis in the process of the broken symmetry electroweak transition in the expanding Universe is the widely discussed model where the baryonic asymmetry is induced by the quantum chiral anomaly. We discuss the modelling of this phenomenon in superfluid 3He and superconductors where the chiral anomaly is realized in the presence of quantized vortex, which introduces the nodes in the energy spectrum of the fermionic quasiparticles. The spectral flow of fermions through the nodes during the vortex motion leads to creation of the fermionic charge from the superfluid vacuum and to transfer of the superfluid linear momentum into the heat bath, thus producing an extra force on the vortex, which in some cases compensates the Magnus force. This spectral-flow force was calculated 20 years ago by Kopnin and Kravtsov for s-wave superconductors, but only recently it was measured in a broad temperature range in Manchester experiments on rotating superfluid 3He. The "momentogenesis" observed in 3He is analogous to the dynamical production of the baryons by cosmic strings. Some other possible scenaria of the baryogenesis related to superfluid 3He are discussed.