| In nanostructures such as quantum dots and single-molecule devices, reduced spatial dimensionality enhances the roles of quantum-mechanical interference and of interactions. Electron-electron interactions give rise to Coulomb blockade and collective screening of a localized spin by lead electrons through the Kondo effect. At the same time, vibrations and other forms of environmental noise act as significant sources of decoherence for the electronic states. This talk will report theoretical studies of the consequences of strong electron-electron and electron-boson coupling in nanostructures, with a focus on the modification of Kondo physics in double dots and two-level molecules. The interplay of interactions can generate effective attraction between electrons confined in the same spatial state, convert conventional (spin-sector) Kondo physics into strong charge-sector correlations, and produce quantum (absolute temperature T = 0) phase transitions that should have clear signatures in the electrical transport at T > 0. |
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