CP violation with hypermagnetic fields and electroweak baryogenesis

We show that in the presence of primordial magnetic fields, it is possible to produce a large enough amount of CP violation to possibly explain the baryon asymmetry of the universe. This can happen during the reflection of fermions off the true vacuum bubbles nucleated during a first order phase transition. The chiral nature of the fermion coupling to the background field in the symmetric phase can be used to construct two-fermion interference processes in analogy to the Bohm-Aharanov effect. By describing the transport of the CP asymmetry into the symmetric phase, it is possible to generate a baryon to entropy ratio ρB/s=(3-6)x10-11, which is close to the observed value based on uncleosynthesis considerations