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Title: Magnetic fields and chiral asymmetry in the early hot universe

Abstract

In this paper, we study analytically the process of external generation and subsequent free evolution of the lepton chiral asymmetry and helical magnetic fields in the early hot universe. This process is known to be affected by the Abelian anomaly of the electroweak gauge interactions. As a consequence, chiral asymmetry in the fermion distribution generates magnetic fields of non-zero helicity, and vice versa. We take into account the presence of thermal bath, which serves as a seed for the development of instability in magnetic field in the presence of externally generated lepton chiral asymmetry. The developed helical magnetic field and lepton chiral asymmetry support each other, considerably prolonging their mutual existence, in the process of 'inverse cascade' transferring magnetic-field power from small to large spatial scales. For cosmologically interesting initial conditions, the chiral asymmetry and the energy density of helical magnetic field are shown to evolve by scaling laws, effectively depending on a single combined variable. In this case, the late-time asymptotics of the conformal chiral chemical potential reproduces the universal scaling law previously found in the literature for the system under consideration. This regime is terminated at lower temperatures because of scattering of electrons with chirality change, which exponentiallymore » washes out chiral asymmetry. We derive an expression for the termination temperature as a function of the chiral asymmetry and energy density of helical magnetic field.« less

Authors:
;  [1];  [2]
  1. Bogolyubov Institute for Theoretical Physics, 03680 Kiev (Ukraine)
  2. Institut für Kernphysik, Johannes Gutenberg Universität, 55128 Mainz (Germany)
Publication Date:
OSTI Identifier:
22679434
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2016; Journal Issue: 10; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASYMMETRY; ASYMPTOTIC SOLUTIONS; CHIRALITY; DISTRIBUTION; ELECTRONS; ENERGY DENSITY; HELICITY; INSTABILITY; INTERACTIONS; MAGNETIC FIELDS; SCATTERING; UNIVERSE

Citation Formats

Sydorenko, Maksym, Shtanov, Yuri, and Tomalak, Oleksandr, E-mail: maxsydorenko@gmail.com, E-mail: tomalak@uni-mainz.de, E-mail: shtanov@bitp.kiev.ua. Magnetic fields and chiral asymmetry in the early hot universe. United States: N. p., 2016. Web. doi:10.1088/1475-7516/2016/10/018.
Sydorenko, Maksym, Shtanov, Yuri, & Tomalak, Oleksandr, E-mail: maxsydorenko@gmail.com, E-mail: tomalak@uni-mainz.de, E-mail: shtanov@bitp.kiev.ua. Magnetic fields and chiral asymmetry in the early hot universe. United States. doi:10.1088/1475-7516/2016/10/018.
Sydorenko, Maksym, Shtanov, Yuri, and Tomalak, Oleksandr, E-mail: maxsydorenko@gmail.com, E-mail: tomalak@uni-mainz.de, E-mail: shtanov@bitp.kiev.ua. Sat . "Magnetic fields and chiral asymmetry in the early hot universe". United States. doi:10.1088/1475-7516/2016/10/018.
@article{osti_22679434,
title = {Magnetic fields and chiral asymmetry in the early hot universe},
author = {Sydorenko, Maksym and Shtanov, Yuri and Tomalak, Oleksandr, E-mail: maxsydorenko@gmail.com, E-mail: tomalak@uni-mainz.de, E-mail: shtanov@bitp.kiev.ua},
abstractNote = {In this paper, we study analytically the process of external generation and subsequent free evolution of the lepton chiral asymmetry and helical magnetic fields in the early hot universe. This process is known to be affected by the Abelian anomaly of the electroweak gauge interactions. As a consequence, chiral asymmetry in the fermion distribution generates magnetic fields of non-zero helicity, and vice versa. We take into account the presence of thermal bath, which serves as a seed for the development of instability in magnetic field in the presence of externally generated lepton chiral asymmetry. The developed helical magnetic field and lepton chiral asymmetry support each other, considerably prolonging their mutual existence, in the process of 'inverse cascade' transferring magnetic-field power from small to large spatial scales. For cosmologically interesting initial conditions, the chiral asymmetry and the energy density of helical magnetic field are shown to evolve by scaling laws, effectively depending on a single combined variable. In this case, the late-time asymptotics of the conformal chiral chemical potential reproduces the universal scaling law previously found in the literature for the system under consideration. This regime is terminated at lower temperatures because of scattering of electrons with chirality change, which exponentially washes out chiral asymmetry. We derive an expression for the termination temperature as a function of the chiral asymmetry and energy density of helical magnetic field.},
doi = {10.1088/1475-7516/2016/10/018},
journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 10,
volume = 2016,
place = {United States},
year = {2016},
month = {10}
}