It is shown how to solve the Euclidean equations of motion of a point
particle in a general potential and in the presence of a four-Fermi term. The
classical action in this theory depends explicitly on a set of four fermionic
collective coordinates. The corrections to the classical action due to the
presence of fermions are of topological nature in the sense that they depend
only on the values of the fields at the boundary points τ→±∞.
As an application, the Sine-Gordon model with a four-Fermi term is solved
explicitly and the corrections to the classical action are computed.Comment: 8 page