A. Tagliacozzo

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Linear conductance across a large quantum dot via a single level epsilon(0) with large hybridization to the contacts is strongly sensitive to quasibound states localized in the dot and weakly coupled to epsilon(0). The conductance oscillates with the gate voltage due to interference of the Fano type. At low temperature and Coulomb blockade, Kondo(More)
A superconductor-semiconducting nanowire-superconductor heterostructure in the presence of spin-orbit coupling and magnetic field can support a supercurrent even in the absence of phase difference between the superconducting electrodes. We investigate this phenomenon—the anomalous Josephson effect—employing a model capable of describing many bands in the(More)
V. Parente,1,2,4 A. Tagliacozzo,1,2 F. von Oppen,3 and F. Guinea4 1Dipartimento di Fisica, Università di Napoli Federico II, Via Cintia, I-80126 Napoli, Italy 2CNR-SPIN, Monte Sant’Angelo-Via Cintia, I-80126 Napoli, Italy 3Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany 4Instituto de Ciencia(More)
We calculate the oscillations of the dc conductance across a mesoscopic ring, simultaneously tuned by applied magnetic and electric fields orthogonal to the ring. The oscillations depend on the Aharonov-Bohm flux and of the spin-orbit coupling. They result from mixing of the dynamical phase, including the Zeeman spin splitting, and of geometric phases. By(More)
The scattering of Dirac electrons by topological defects could be one of the most relevant sources of resistance in graphene and at the boundary surfaces of a three-dimensional topological insulator (3D TI). In the long wavelength, continuous limit of the Dirac equation, the topological defect can be described as a distortion of the metric in curved space,(More)
Self-assembled YBaCuO diffusive grain boundary submicron Josephson junctions offer a realization of a special regime of the proximity effect, where normal state coherence prevails on the superconducting coherence in the barrier region. Resistance oscillations from the current-voltage characteristic encode mesoscopic information on the junction and more(More)
Abstract. We show that a junction of three off-critical quantum Ising chains can be regarded as a quantum spin chain realization of the two-channel spin-1/2 overscreened Kondo effect with two superconducting leads. We prove that, as long as the Kondo temperature is larger than the superconducting gap, the equivalent Kondo model flows towards the 2 channel(More)
D. Giuliano, P. Sodano and A. Tagliacozzo 1 I.N.F.M. “Coherentia” and Unita’ di Napoli 2 Dipartimento di Scienze Fisiche, Università di Napoli “Federico II”, Monte S.Angelo via Cintia, I-80126 Napoli, Italy 3 Dipartimento di Fisica, Università di Perugia, via Pascoli 0163, Perugia, Italy 4 I.N.F.N., Sezione di Perugia 5 Dipartimento di Fisica, Università(More)
We apply a Gutzwiller-like variational technique to study Josephson conduction across a quantum dot with an odd number of electrons connected to two superconducting leads. Our method projects out all states on the dot but the Kondo singlet and is valid when Kondo correlations are dominant and no Andreev bound states localized at the dot are available for(More)
Magneto-fluctuations of the normal resistance RN have been reproducibly observed in YBa2Cu3O7-d biepitaxial grain boundary junctions at low temperatures. We attribute them to mesoscopic transport in narrow channels across the grain boundary line, occurring even in the presence of large voltage drops. The Thouless energy appears to be the relevant energy(More)