  We study the transport properties of two electrons in a quasi one-dimensional
disordered wire. The electrons are subject to both, a disorder potential and a
short range two-body interaction. Using the approach developed by Iida et al. [
Ann. Phys. (N.Y.) 200 (1990) 219 ], the supersymmetry technique, and a suitable
truncation of Hilbert space, we work out the two-point correlation function in
the framework of a non-linear sigma model. We study the loop corrections to
arbitrary order. We obtain a remarkably simple and physically transparent
expression for the change of the localization length caused by the two-body
interaction.
