Introducing Quarks in Confining Strings via the Fermionic Wilson Loop
  In the world line representation of the fermionic effective action for QCD the interaction between Fermions and the gauge field is contained in the fermionic Wilson loop, namely the Wilson loop for a spin-half particle. It is argued that a string representation of the fermionic Wilson loop can provide a link connecting QCD with a dual description of a meson as a quark and an antiquark connected by a string. This is illustrated by obtaining such a representation in compact U(1) gauge theories. The resulting description contains information about the interaction of the spin of the quark with the world sheet degrees of freedom. Such interactions may be of importance in the realization of chiral symmetry in the string picture of QCD, and for delineating the possible presence of a world sheet supersymmetry in QCD strings. 
Vikram Vyas