TITLE:
The Efficiency of CP-Violating α2-Dynamos from Primordial Cosmic Axion Oscillation with Torsion
AUTHORS:
L. C. Garcia de Andrade
KEYWORDS:
Torsion Theories, Axion Dynamo, Primordial Magnetic Fields
JOURNAL NAME:
International Journal of Astronomy and Astrophysics,
Vol.5 No.1,
March
26,
2015
ABSTRACT: Recently
torsion fields were introduced in CP-violating cosmic axion a2-dynamos
[Garcia de Andrade, Mod Phys Lett A, (2011)] in order to obtain Lorentz
violating bounds for torsion. Here instead, oscillating axion solutions of the
dynamo equation with torsion modes [Garcia de Andrade, Phys Lett B (2012)] are
obtained taking into account dissipative torsion fields. Magnetic helicity
torsion oscillatory contribution is also obtained. Note that the torsion presence
guarantees dynamo efficiency when axion dynamo length is much stronger than the
torsion length. Primordial axion oscillations due to torsion yield a magnetic
field of 109 G at Nucleosynthesis epoch. This is obtained due to a
decay of BBN magnetic field of 1015 G induced by torsion. Since
torsion is taken as 10–20 s–1, the dynamo efficiency is
granted over torsion damping. Of course dynamo efficiency is better in the
absence of torsion. In the particular case when the torsion is obtained from
anomalies it is given by the gradient of axion scalar [Duncan et al., Nuclear Phys B 87, 215] that a
simpler dynamo equation is obtained and dynamo mechanism seems to be efficient
when the torsion helicity, is negative while magnetic field decays when the
torsion is positive. In this case an extremely huge value for the magnetic
field of 1015 Gauss is obtained. This is one order of magnitude
greater than the primordial magnetic fields of the domain wall. Actually if one
uses tDW ~ 10-4 s one obtains BDW ~ 1022 G which is a
more stringent limit to the DW magnetic primordial field.