Induced Connections in Field Theory: The Odd-Dimensional Yang-Mills Case
  We consider $SU(N)$ Yang-Mills theories in $(2n+1)$-dimensional Euclidean spacetime, where $N\geq n+1$, coupled to an even flavour number of Dirac fermions. After integration over the fermionic degrees of freedom the wave functional for the gauge field inherits a non-trivial $U(1)$-connection which we compute in the limit of infinite fermion mass. Its Chern-class turns out to be just half the flavour number so that the wave functional now becomes a section in a non-trivial complex line bundle. The topological origin of this phenomenon is explained in both the Lagrangean and the Hamiltonian picture. 
Domenico Giulini