http://dspace-roma3.caspur.it The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Search the Channel search http://dspace-roma3.caspur.it/simple-search http://hdl.handle.net/2307/215 <Title>Tuning the spin Hall effect in a two-dimensional electron gas </Title><br/><Authors>Raimondi, Roberto; Schwab, Peter </Authors><br/><Journal>Europhysics Letters </Journal><br/><Volume>87 </Volume><br/><Issue Date>2009-08 </Issue Date><br/><Pages>37008 </Pages><br/><Abstract>We provide a theoretical framework for the electric fieldcontrol of the electron spin in systems with diffusive electronmotion. The approach is valid in the experimentally important casewhere both intrinsic and extrinsic spin-orbit interaction in a two-dimensional electron gas are present simultaneously. Surprisingly, even when the extrinsic mechanism is the dominant drivingforce for spin Hall currents, the amplitude of the spin Hallconductivity may be considerably tuned by varyingthe intrinsic spin-orbit coupling via a gate voltage.Furthermore we provide an explanation for the mechanism giving rise to theexperimentally observed out-of-plane spin polarization in a (110) GaAsquantum well. </Abstract> http://hdl.handle.net/2307/214 <Title>I principi di proporzionalità e neutralità nella disciplina dei servizi d'interesse economico generale </Title><br/><Authors>Gualtieri, Francesco </Authors><br/><Issue Date>2008-05-07 </Issue Date> http://hdl.handle.net/2307/213 <Title>Selezione di Nuclei Galattici Attivi nel medio-infrarosso </Title><br/><Authors>Sacchi, Nicola </Authors><br/><Issue Date>2008-02-27 </Issue Date> http://hdl.handle.net/2307/212 <Title>Andreev tunneling in quantum dots: A slave-boson approach </Title><br/><Authors>Schwab, Peter; Raimondi, Roberto </Authors><br/><Journal>Physical Review B </Journal><br/><Volume>59 </Volume><br/><Issue Date>1999 </Issue Date><br/><Pages>1637 - 1640 </Pages><br/><Abstract>We study a strongly interacting quantum dot connected to a normal and to a superconducting lead. By means of the slave-boson technique we investigate the low-temperature regime and discuss electrical transport through the dot. At the level of mean-field approximation we are able to discuss both limits of small and large Δ/TK, where Δ is the superconducting gap and TK is the Kondo temperature. We also find that the zero-bias anomaly in the current-voltage characteristics, which is associated with the occurrence of the Kondo resonance in the quantum dot, is enhanced in the presence of superconductivity, due to resonant Andreev scattering. </Abstract> http://hdl.handle.net/2307/211 <Title>Nonlinear effects and dephasing in disordered electron systems </Title><br/><Authors>Raimondi, Roberto; Schwab, Peter; Castellani, Claudio </Authors><br/><Journal>Physical Review B </Journal><br/><Volume>60 </Volume><br/><Issue Date>1999 </Issue Date><br/><Pages>5818 - 5831 </Pages><br/><Abstract>The calculation of the dephasing time in electron systems is presented. By means of the Keldysh formalism, we discuss in a unifying way both weak localization and interaction effects in disordered systems. This allows us to show how dephasing arises both in the particle-particle channel (weak localization) and in the particle-hole channel (interaction effect). First we discuss dephasing by an external field. Besides reviewing previous work on how an external oscillating field suppresses the weak localization correction, we derive a new expression for the effect of a field on the interaction correction. We find that the latter may be suppressed by a static electric field, in contrast to weak localization. We then consider dephasing due to inelastic scattering. The ambiguities involved in the definition of the dephasing time are clarified by directly comparing the diagrammatic approach with the path-integral approach. We show that different dephasing times appear in the particle-particle and particle-hole channels. Finally we comment on recent experiments. </Abstract> http://hdl.handle.net/2307/210 <Title>Propertiesof superconductor-Luttinger liquid hybrid systems </Title><br/><Authors>Fazio, Rosario; Hekking, Frank W J; Odintsov, A A; Raimondi, Roberto </Authors><br/><Journal>Superlattices and Microstructures </Journal><br/><Volume>25 </Volume><br/><Issue Date>1999 </Issue Date><br/><Pages>1163-1175 </Pages><br/><Abstract>In this paper, we review some recent results concerning the physics of superconductor–Luttinger-liquid proximity systems. We discuss both equilibrium (the pair amplitude, Josephson current, and the local density of states) and nonequilibrium (the subgap current) properties. </Abstract> http://hdl.handle.net/2307/209 <Title>Lower and upper Hubbard bands: A slave-boson treatment </Title><br/><Authors>Raimondi, Roberto; Castellani, Claudio </Authors><br/><Journal>Physical Review B </Journal><br/><Volume>48 </Volume><br/><Issue Date>1993 </Issue Date><br/><Pages>11453 - 11456 </Pages><br/><Abstract>We analyze the single-particle spectral density and the optical conductivity of the single-band Hubbard model in the insulating Mott phase within the slave-boson technique. We show that the boson fluctuations around the saddle-point solution build up the lower and upper Hubbard bands and give rise to the optical conductivity which describes transitions between these incoherent bands. We find that the Brinkman-Rice metal-insulator transition is characterized by the simultaneous vanishing of the jump in the chemical potential, the single-particle spectral density gap, and the optical gap. </Abstract> http://hdl.handle.net/2307/208 <Title>Gli elementi normativi nelle cause di giustificazione </Title><br/><Authors>Cori, Claudia </Authors><br/><Issue Date>2008-04-23 </Issue Date> http://hdl.handle.net/2307/207 <Title>Il potere sanzionatorio della Commissione di garanzia dell'attuazione della legge sullo sciopero nei servizi pubblici essenziali </Title><br/><Authors>Nanni, Rossana </Authors><br/><Issue Date>2008-05-09 </Issue Date> http://hdl.handle.net/2307/206 <Title>Il nuovo Orfeo di Virgilio : un mito riscritto (georg. 4, 453-527) </Title><br/><Authors>Mazza, Teresa </Authors><br/><Issue Date>2008-04-11 </Issue Date>