INCOMMENSURATE POTENTIALS - ANALYTIC AND NUMERICAL PROGRESS

Incommensurate potentials present quite peculiar physical properties d ue to the deterministic break of translational symmetry; among others we mention generalized metal-insulator transitions, mobility edges and the singular behaviour of localization length. We stress here how the se aspects can be fruitfully described by the joint use of the renorma lization procedure and an appropriate envelope function formalism. The application to some significant examples clearly reveals that our app roach is well suited to treat more complex and realistic incommensurat e potentials.