Primordial magnetic fields from selfordering scalar fields
Abstract
A symmetrybreaking phase transition in the early universe could have led to the formation of cosmic defects. Because these defects dynamically excite not only scalar and tensor type cosmological perturbations but also vector type ones, they may serve as a source of primordial magnetic fields. In this study, we calculate the time evolution and the spectrum of magnetic fields that are generated by a type of cosmic defects, called global textures, using the nonlinear sigma (NLSM) model. Based on the standard cosmological perturbation theory, we show, both analytically and numerically, that a vectormode relative velocity between photon and baryon fluids is induced by textures, which inevitably leads to the generation of magnetic fields over a wide range of scales. We find that the amplitude of the magnetic fields is given by B∼10{sup −9}((1+z)/10{sup 3}){sup −2.5}(v/m{sub pl}){sup 2}(k/Mpc{sup −1}){sup 3.5}/√N Gauss in the radiation dominated era for k∼< 1 Mpc{sup −1}, with v being the vacuum expectation value of the O(N) symmetric scalar fields. By extrapolating our numerical result toward smaller scales, we expect that B∼ 10{sup −14.5}((1+z)/10{sup 3}){sup 1/2}(v/m{sub pl}){sup 2}(k/Mpc{sup −1}){sup 1/2}/√N Gauss on scales of k∼> 1 Mpc{sup −1} at redshift 0z∼> 110. This might be a seed of the magnetic fieldsmore »
 Authors:
 Department of Physics and Astrophysics, Nagoya University, Aichi 4648602 (Japan)
 Helsinki Institute of Physics, University of Helsinki, PO Box 64, FIN00014 (Finland)
 Publication Date:
 OSTI Identifier:
 22525905
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 04; Other Information: Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BARYONS; EXPECTATION VALUE; INTERSTELLAR MAGNETIC FIELDS; NONLINEAR PROBLEMS; PERTURBATION THEORY; PHASE TRANSFORMATIONS; PHOTONS; RED SHIFT; SCALAR FIELDS; SCALARS; SYMMETRY BREAKING; UNIVERSE; VECTOR FIELDS
Citation Formats
Horiguchi, Kouichirou, Ichiki, Kiyotomo, Sugiyama, Naoshi, and Sekiguchi, Toyokazu, Email: horiguchi.kouichirou@h.mbox.nagoyau.ac.jp, Email: ichiki@a.phys.nagoyau.ac.jp, Email: toyokazu.sekiguchi@helsinki.fi, Email: naoshi@nagoyau.jp. Primordial magnetic fields from selfordering scalar fields. United States: N. p., 2015.
Web. doi:10.1088/14757516/2015/04/007.
Horiguchi, Kouichirou, Ichiki, Kiyotomo, Sugiyama, Naoshi, & Sekiguchi, Toyokazu, Email: horiguchi.kouichirou@h.mbox.nagoyau.ac.jp, Email: ichiki@a.phys.nagoyau.ac.jp, Email: toyokazu.sekiguchi@helsinki.fi, Email: naoshi@nagoyau.jp. Primordial magnetic fields from selfordering scalar fields. United States. doi:10.1088/14757516/2015/04/007.
Horiguchi, Kouichirou, Ichiki, Kiyotomo, Sugiyama, Naoshi, and Sekiguchi, Toyokazu, Email: horiguchi.kouichirou@h.mbox.nagoyau.ac.jp, Email: ichiki@a.phys.nagoyau.ac.jp, Email: toyokazu.sekiguchi@helsinki.fi, Email: naoshi@nagoyau.jp. 2015.
"Primordial magnetic fields from selfordering scalar fields". United States.
doi:10.1088/14757516/2015/04/007.
@article{osti_22525905,
title = {Primordial magnetic fields from selfordering scalar fields},
author = {Horiguchi, Kouichirou and Ichiki, Kiyotomo and Sugiyama, Naoshi and Sekiguchi, Toyokazu, Email: horiguchi.kouichirou@h.mbox.nagoyau.ac.jp, Email: ichiki@a.phys.nagoyau.ac.jp, Email: toyokazu.sekiguchi@helsinki.fi, Email: naoshi@nagoyau.jp},
abstractNote = {A symmetrybreaking phase transition in the early universe could have led to the formation of cosmic defects. Because these defects dynamically excite not only scalar and tensor type cosmological perturbations but also vector type ones, they may serve as a source of primordial magnetic fields. In this study, we calculate the time evolution and the spectrum of magnetic fields that are generated by a type of cosmic defects, called global textures, using the nonlinear sigma (NLSM) model. Based on the standard cosmological perturbation theory, we show, both analytically and numerically, that a vectormode relative velocity between photon and baryon fluids is induced by textures, which inevitably leads to the generation of magnetic fields over a wide range of scales. We find that the amplitude of the magnetic fields is given by B∼10{sup −9}((1+z)/10{sup 3}){sup −2.5}(v/m{sub pl}){sup 2}(k/Mpc{sup −1}){sup 3.5}/√N Gauss in the radiation dominated era for k∼< 1 Mpc{sup −1}, with v being the vacuum expectation value of the O(N) symmetric scalar fields. By extrapolating our numerical result toward smaller scales, we expect that B∼ 10{sup −14.5}((1+z)/10{sup 3}){sup 1/2}(v/m{sub pl}){sup 2}(k/Mpc{sup −1}){sup 1/2}/√N Gauss on scales of k∼> 1 Mpc{sup −1} at redshift 0z∼> 110. This might be a seed of the magnetic fields observed on large scales today.},
doi = {10.1088/14757516/2015/04/007},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 04,
volume = 2015,
place = {United States},
year = 2015,
month = 4
}

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