It is pointed out that, contrary to some claims in the literature, the domain walls cannot be a source of a correlated at large scales primordial magnetic field, even if the fermionic modes bound on the wall had ferromagnetic properties. In a particular model with massive (2 + 1)-dimensional fermions bound to a domain wall, previously claimed to exhibit a ferromagnetic behavior, it is explicitly shown that the fermionic system in fact has properties of a normal diamagnetic with the susceptibility vanishing at high temperature. (C) 2000 Published by Elsevier Science B.V.
|Original language||English (US)|
|Number of pages||6|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - Oct 19 2000|
Bibliographical noteFunding Information:
Summarizing the discussion of this paper, we conclude that the gas of modes of charged Dirac fermions on a domain wall is always diamagnetic with susceptibility vanishing at high temperature. Therefore such systems cannot spontaneously produce any correlated magnetic field. The spontaneous magnetization of the modes for neutral fermions with anomalous magnetic moment is proportional to the surface density of the fermion number on the wall, and the magnetic field generated by a spontaneous magnetization of a wall is suppressed by the inverse of the wall's dimension. These considerations lead us to the general conclusion that it is at least highly unlikely that domain walls can provide a physically viable source of the primordial magnetic field. This work is supported in part by DOE under the grant number DE-FG02-94ER40823.