REAL-SPACE ELECTRON PAIRING IN 2-DIMENSIONAL SYSTEMS

The local-pairing problem of two electrons with parallel and anti-para llel spins is analysed by looking at the pairing energy, the coherence length and the mobility of pairs in a square lattice. These physical quantities am calculated by a novel method based on mapping the Hubbar d problem onto a tight-binding one in a higher-dimensional space, whic h can be solved exactly.