Electroweak Strings, Zero Modes and Baryon Number
  The Dirac equations for leptons and quarks in the background of an electroweak $Z-$string have zero mode solutions. If two loops of electroweak string are linked, the zero modes on one of the loops interacts with the other loop via an Aharanov-Bohm interaction. The effects of this interaction are briefly discussed and it is shown that the fermions induce a baryon number on linked loops of $Z-$string. (Submitted to Proceedings of "Trends in Astrophysics" Conference, Stockholm, 1994.) 
Tanmay Vachaspati