title: Generation of magnetic fields and gravitational waves at neutrino decoupling.
abstract: We show that an inhomogeneous cosmological lepton number may have produced turbulence in the primordial plasma when neutrinos entered the (almost) free-streaming regime. This effect may be responsible for the origin of cosmic magnetic fields and give rise to a detectable background of gravitational waves. An existence of inhomogeneous lepton asymmetry could be naturally generated by active-sterile neutrino oscillations or by some versions of the Affleck-Dine baryogenesis scenario.
authors.affiliation: I.N.F.N., Sezione di Ferrara, Via del Paradiso 12, 44100 Ferrara, Italy.
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Dolgov
authors.forename: Dario
authors.initials: D
authors.lastname: Grasso