Primordial Magnetic Fields from Out of Equilibrium Cosmological Phase Transitions

Journal Article · Wed Sep 28 00:00:00 EDT 2005 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2077205· OSTI ID:20719374

Boyanovsky, D ^[1]; Vega, H.J. de ^[2]

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1. Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)
2. LPTHE, Universite Pierre et Marie Curie (Paris VI) et Denis Diderot (Paris VII), Laboratoire Associe au CNRS UMR 7589, Tour 24, 5eme. etage, 4, Place Jussieu, 75252 Paris, Cedex 05 (France)

The universe cools down monotonically following its expansion. This generates a sequence of phase transitions. If a second order phase transition happens during the radiation dominated era with a charged order parameter, spinodal unstabilities generate large numbers of charged particles. These particles hence produce magnetic fields. We use out of equilibrium field theory methods to study the dynamics in a mean field or large N setup. The dynamics after the transition features two distinct stages: a spinodal regime dominated by linear long-wavelength instabilities, and a scaling stage in which the non-linearities and backreaction of the scalar fields are dominant. This second stage describes the growth of horizon sized domains. We implement a formulation based on the non-equilibrium Schwinger-Dyson equations to obtain the spectrum of magnetic fields that includes the dissipative effects of the plasma. We find that large scale magnetogenesis is efficient during the scaling regime. Charged scalar field fluctuations with wavelengths of the order of the Hubble radius induce large scale magnetogenesis via loop effects. The leading processes are: pair production, pair annihilation and low energy bremsstrahlung, these processes while forbidden in equilibrium are allowed strongly out of equilibrium. The ratio between the energy density on scales larger than L and that in the background radiation r(L,T) {rho}B(L,T)/{rho}cmb(T) is r(L,T) {approx} 10-34 at the Electroweak scale and r(L,T) {approx} 10-14 at the QCD scale for L {approx} 1 Mpc. The resulting spectrum is insensitive to the magnetic diffusion length and equipartition between electric and magnetic fields does not hold. We conjecture that a similar mechanism could be operative after the QCD chiral phase transition.

• OSTI ID: 20719374
• Journal Information: AIP Conference Proceedings, Vol. 784, Issue 1; Conference: International conference on magnetic fields in the universe: From laboratory and stars to primordial structures, Angra dos Reis (Brazil), 28 Nov - 3 Dec 2004; Other Information: DOI: 10.1063/1.2077205; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANNIHILATION
BACKGROUND RADIATION
BREMSSTRAHLUNG
CHARGED PARTICLES
CHIRALITY
COSMOLOGY
DIFFUSION LENGTH
ENERGY DENSITY
EQUATIONS
EQUILIBRIUM
GAUGE INVARIANCE
MAGNETIC FIELDS
MEAN-FIELD THEORY
ORDER PARAMETERS
PAIR PRODUCTION
PHASE TRANSFORMATIONS
PLASMA
QUANTUM CHROMODYNAMICS
SCALAR FIELDS
UNIVERSE