Ponente
Dr.
Maxim Dvornikov
(Institute of Physics, University of Sao Paulo)
Descripción
We study the generation of strong magnetic fields in magnetars and in the early universe. For this purpose we calculate the antisymmetric contribution to the photon polarization tensor in medium consisting of electron-positron plasma and a gas of neutrinos and antineutrinos, interacting within the Standard Model. Such a contribution exactly takes into account the temperature and the chemical potential of plasma as well as the photon dispersion law in this background matter. Using this result we derive the Faraday equation for the magnetic field evolution which accounts for the parity violating interaction between electrons and neutrinos. On the basis of the Faraday equation we predict the instability of a seed magnetic field and its growth provided a nonzero asymmetry between neutrinos and antineutrinos is present. We apply our result to the magnetic field amplification, driven by the electron neutrinos asymmetry, during the first second of a supernova explosion. It is suggested that this mechanism can explain strong magnetic fields of magnetars. Then we study the cosmological magnetic field evolution driven by the neutrino asymmetry density. Within this approach we find a lower bound on the neutrino asymmetries consistent with the well-known Big Bang nucleosynthesis bound in a hot universe plasma.
M. Dvornikov and V. B. Semikoz, to be published in JCAP (2014); arXiv:1311.5267 [hep-ph].
Autor primario
Dr.
Maxim Dvornikov
(Institute of Physics, University of Sao Paulo)
