Abstract
Localization in a random system yields a conductance G, which is supersensitive to the Fermi energy. Few extraelectrons may increase or decrease G by orders of magnitude. The resulting (extra-multiple, extra-high and extra-narrow) resonances are specific for each system and related to its microscopic structure. Resonances survive up to reasonable temperatures. Their nature and characteristics are considered, as well as their generality; they are typical for the proparation of any waves through a system, where they may be localized and where energy dissipation is very low. © 1984 Elsevier Science Publishers B.V.