Primordial hypermagnetic knots

Topologically nontrivial configurations of the hypermagnetic flux lines lead to the formation of hypermagnetic knots (HKs) whose decay might seed the baryon asymmetry of the universe. HKs can be dynamically generated provided a topologically trivial (i.e., stochastic) distribution of flux lines is already present in the symmetric phase of the electroweak (EW) theory. In spite of the mechanism generating the HKs, their typical size must exceed the diffusivity length scale. In the minimal standard model (but not necessarily in its supersymmetric extension) HKs are washed out. A classical hypermagnetic background in the symmetric phase of the EW theory can produce interesting amounts of gravitational radiation.