Strong correlation effects in mesoscopic systems

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A mesoscopic system is really like a large molecule (with a size between the nano and the micron), but in practice it is always, at least weakly, coupled to a much larger, essentially infinite, system. Ideally, one would like to interpolate between open and closed systems by varying some coupling strengths. The interest in investigating electron systems in the intermediate size range between microscopic and macroscopic, sometimes referred to as ''mesoscopic'' (a word coined by Van Kampen in 1981), is not only to understand the macroscopic limit and how it is achieved by, say, building up larger and larger clusters to go from the ''molecule'' to the ''bulk''; many novel phenomena exist that are intrinsic to mesoscopic systems. In fact, the special phenomena that exist in this mesoscopic range are of great interest by themselves. Many of the usual rules that one is used to in macroscopic physics may not hold in mesoscopic systems. For example, the rules for addition of resistances, both in series and in parallel, are different and more complicated. The electronic motion is definitely wavelike which emphasizes the importance of quantum mechanics. As a matter of fact, mesoscopic systems which behave like large artificial atoms are inevitably governed by "strong repulsion" effects between electrons resulting in a plethora of fascinating and unprecedented phenomena such as the Coulomb blockade effect allowing to build single-electron transistors, the appearance of excitations which eventually possess charges that are less than the elementary charge "e" of an electron, the so-called 0.7 anomaly occurring in conductance experiments through short quantum point contacts,... . Our theoretical proposal aims to predict novel physical laws governing mesoscopic electron systems that might stem from strong interaction effects, to understand properly the role of parasitic macroscopic degrees of freedom such as phonons or electromagnetic noise leading to quantum decoherence, to contrive novel solid-state settings that might produce and detect the entanglement between two artifical atoms or qubits, and finally by introducing Mechanics into this Quantum World by studying for instance how the vibrations of a nanodevice influence its transport properties.