Ferromagnetic properties of charged vector boson condensate

TL;DR

This paper investigates the ferromagnetic and antiferromagnetic phases of W boson condensates in the early universe, proposing mechanisms for primordial magnetic field generation and exploring effects of modified theories.

Contribution

It demonstrates that W boson condensates can form ferromagnetic states in the standard model, potentially seeding cosmic magnetic fields, and also explores conditions for antiferromagnetic condensates in modified theories.

Findings

Ferromagnetic W condensates can generate primordial magnetic fields.

Antiferromagnetic condensates involve scalar charge density with small field values.

The phase depends on the theory's parameters like self-interactions and mixing angle.

Abstract

Bose-Einstein condensation of W bosons in the early universe is studied. It is shown that, in the broken phase of the standard electroweak theory, condensed W bosons form a ferromagnetic state with aligned spins. In this case the primeval plasma may be spontaneously magnetized inside macroscopically large domains and form magnetic fields which may be seeds for the observed today galactic and intergalactic fields. However, in a modified theory, e.g. in a theory without quartic self interactions of gauge bosons or for a smaller value of the weak mixing angle, antiferromagnetic condensation is possible. In the latter case W bosons form scalar condensate with macroscopically large electric charge density i.e. with a large average value of the bilinear product of W-vector fields but with microscopically small average value of the field itself.