Speaker
Maxim Dvornikov
(USP)
Description
I study the generation of cosmic magnetic fields in the primordial plasma of the early universe. A strong large scale magnetic field can be created owing to the instability caused by the parity violating interaction between charged leptons and neutrino-antineutrino gas. For this purpose I calculate the most general expression for the Chern-Simons parameter in this background matter using the imaginary time QFT at finite temperature. Basing on this result I derive the modified Faraday equation which describes the magnetic field evolution. If a nonzero neutrino asymmetry is present, a seed magnetic field can be dynamo amplified. Assuming the causal scenario, i.e. the length scale of the magnetic field being less than the horizon, I obtain the new lower bound on the neutrino asymmetries $\xi = \mu_\nu / T$, where $\mu_\nu$ is the chemical potential of the $\nu\bar{\nu}$ gas and $T$ is its temperature, which is consistent with the well-known Big Bang nucleosynthesis upper bound on $\xi$ in a hot universe plasma. I also discuss the application of the developed formalism for the magnetic fields generation in other astrophysical media.
References:
1. M. Dvornikov and V. B. Semikoz, JCAP 05 (2014) 002; arXiv:1311.5267.
2. M. Dvornikov, Phys. Rev. D 90, 041702 (2014); arXiv:1405.3059.
3. M. Dvornikov and V. B. Semikoz, to be submitted to the arXiv soon.
Author
Maxim Dvornikov
(USP)
