Primordial Magnetic Helicity from Stochastic Electric Currents

Understand

We study the possibility that primordial magnetic fields generated in the transition between inflation and reheating posses magnetic helicity, $H_M$.

• The fields are induced by stochastic currents of scalar charged particles created during the mentioned transition.
• We estimate the rms value of the induced magnetic helicity by computing different four-point SQED Feynman diagrams.
• For any considered volume, the magnetic flux across its boundaries is in principle non null, which means that the magnetic helicity in those regions is gauge dependent.