Families index theorem in supersymmetric WZW model and twisted K-theory
  The construction of twisted K-theory classes on a compact Lie group is reviewed using the supersymmetric Wess-Zumino-Witten model on a cylinder. The Quillen superconnection is introduced for a family of supercharges and the Chern character for the family is given and its relation to twisted cohomology is discussed. 
Jouko Mickelsson