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Posters Non-adiabatically driven electron in quantum wire T. Cadez 1 , J. H. Jefferson 2 and A. Ramsak 1,3 1 J. Stefan Institute, Ljubljana, Slovenia 2 Department of Physics, Lancaster University, Lancaster LA1 4YB, UK 3 Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia An exact solution is derived for the wave function of an electron in a semiconductor quantum wire with spin-orbit interaction and driven by external time dependent harmonic confining potential [1]. The formalism allows analytical expressions for various quantities to be derived, such as spin and pseudo-spin rotations, energy and occupation probabilities for excited states. It is demonstrated how perfect spin and pseudo-spin flips can be achieved at high frequencies of order , the confining potential level spacing. By an appropriately chosen driving term, spin manipulation can be exactly performed far into the non-adiabatic regime. Implications for spin-polarised emission and spin-dependent transport are also discussed. [1] T. Cadez, J. H. Jefferson and A. Ramsak, Non-adiabatically driven electron in quantum wire, arXiv: 1208.5359 __________________________________________________________________________ Spin-orbit effects in nanowire-based wurtzite semiconductor quantum dots Guido Intronati (1,2,3) , Pablo Tamborenea (1) , Rodolfo Jalabert (2) , Dietmar Weinmann (2) (1) Departamento de Física, Universidad de Buenos Aires, Ciudad Universitaria, Pab. I, C1428EHA Buenos Aires, Argentina (2) Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, CNRS-UdS, 23 rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France (3) Service de Physique de l'Etat Condensé CNRS URA 2464, CEA Saclay, 91191 Gif-sur- Yvette, France We study the effects of spin-orbit interaction on the electronic states and spin relaxation rates of cylindrical quantum dots defined on wurtzite quantum wires. The linear and cubic contributions of the bulk Dresselhaus spin-orbit coupling are taken into account, along with the influence of an external magnetic field. An analytic solution for the electronic states that was previously found for cylindrical pillbox zincblende quantum dots with Rashba interaction is extended here to the case of wurtzite dots. The energy spectrum is computed, and the electronic states for InAs are characterized. This may be a useful aspect of this compound from the point of view of applications to spin manipulation.
Posters Nonclassical photon-pair production in a voltage-biased Josephson junction Juha Leppäkangas 1 , Göran Johansson 1 , Michael Marthaler 2 , and Mikael Fogelström 1 1 Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden 2 Institut für Theoretische Festkörperphysik and DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology, D-76128 Karlsruhe, Germany We investigate electromagnetic radiation emitted by a small voltage-biased Josephson junction connected to a superconducting transmission line. For weak tunneling couplings and frequencies below the well known emission peak at the Josephson frequency (2eV/h), extra radiation is triggered by quantum noise in the electromagnetic environment. For typical ohmic transmission lines, the corresponding photon flux spectrum becomes symmetric around half the Josephson frequency, indicating that the photons are predominately created in pairs. By establishing an input-output formalism for the microwave field in the transmission line, we give further evidence for this non-classical photon pair production, demonstrating that it violates the classical Cauchy-Schwarz inequality for two-mode flux cross correlations. In connection to recent experiments [1], we also consider a stepped transmission line, where resonances increase the signal-to-noise ratio. [1] M. Hofheinz, F. Portier, Q. Baudouin, P. Joyez, D. Vion, P. Bertet, P. Roche, and D. Esteve Bright Side of the Coulomb Blockade, Phys. Rev. Lett. 106 217005 (2011) __________________________________________________________________________ Gap Generation in Topological Insulator Surface States by non-Ferromagnetic Magnets László Oroszlány 1 , Alberto Cortijo 2 1 Department of Physics of Complex Systems, Eotvos University, H-1117 Budapest, Pázmány Péter sétány 1/A, Hungary 2 Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain. Within a tight binding approach, it is shown that, contrary to the naive expectation, single particle spectral gaps can be opened on the surface states of three dimensional topological insulators by using commensurate out- and in-plane antiferromagnetic or ferromagnetic insulating thin films [1]. [1] L. Oroszlány, A. Cortijo arXiv:1208.4615 __________________________________________________________________________ Optical conductivity of bilayer graphene in the far-infrared (FIR) spectral range Gábor Széchenyi, József Cserti Department of Physics of Complex Systems, Eötvös University, Budapest, Hungary Using Kubo formula we study theoretically the frequency dependent optical conductivity in bilayer graphene with symmetry breaking mechanisms. We demonstrate that in the FIR spectral range (1.2-80 meV) the spectrum is strongly sensitive to the rate of the symmetry breaking, the trigonal warping and the polarization of the light. We show analytically a connection between the minimal conductivity and the zero frequency limit of the optical spectrum.
Page 1 and 2: 2012 22 Octobre 27 Octobre WORKSHOP
Page 3 and 4: Afternoon Morning Timetable Monday
Page 5 and 6: 15h50 - 16h20 Coffee Break 16h20 -
Page 7 and 8: Monday Abstracts Monday, October 22
Page 9 and 10: Monday Single-Electron Tunneling an
Page 11 and 12: Tuesday Tuesday, October 23 Random-
Page 13 and 14: Tuesday the energy level spacings a
Page 15 and 16: Tuesday Electron refrigeration by n
Page 17 and 18: Wednesday [4] K. Saito, G. Benenti,
Page 19 and 20: Thursday [3] B. A. Bernevig, T. L.
Page 21 and 22: Thursday Electronic standing waves
Page 23 and 24: Friday Nanoscale inhomogeneities in
Page 25 and 26: Friday Electron focusing in graphem
Page 27 and 28: Friday molecules. We explain the or
Page 29: Posters Posters Ab-initio study of

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