Now showing items 21-40 of 50

    • Thumbnail

      Energy and momentum transfer in one-dimensional trapped gases by stimulated light scattering 

      Fabbri, N.; Fort, C.; Modugno, Michele; Rosi, S.; Inguscio, M. (IOP Publishing, 2015-06-10)
      In ultracold atoms settings, inelastic light scattering is a preeminent technique to reveal static and dynamic properties at nonzero momentum. In this work, we investigate an array of one-dimensional trapped Bose gases, ...
    • Thumbnail

      Entanglement and extreme spin squeezing of unpolarized states 

      Vitagliano, Giuseppe; Apellániz Asategui, Jagoba; Kleinmann, Matthias; Lücke, Bernd; Klempt, Carsten; Tóth, Géza (IOP Publishing, 2017-01-20)
      We present criteria to detect the depth of entanglement in macroscopic ensembles of spin-j particles using the variance and second moments of the collective spin components. The class of states detected goes beyond traditional ...
    • Thumbnail

      Entanglement negativity in the harmonic chain out of equilibrium 

      Eisler, Viktor; Zimborás, Zoltán (IOP Publishing, 2014-12-08)
      We study the entanglement in a chain of harmonic oscillators driven out of equilibrium by preparing the two sides of the system at different temperatures, and subsequently joining them together. The steady state is constructed ...
    • Thumbnail

      Fitting BICEP2 with defects, primordial gravitational waves and dust 

      Lizarraga Olano, Joanes; Urrestilla Urizabal, Jon; Daverio, David; Hindmarsh, Mark; Kunz, Martin; Liddle, Andrew R. (IOP Publishing, 2015)
      In this work we discuss the possibility of cosmic defects being responsible for the B-mode signal measured by the BICEP2 collaboration. We also allow for the presence of other cosmological sources of B-modes such as ...
    • Thumbnail

      Germanene: a novel two-dimensional germanium allotrope akin to graphene and silicene 

      Dávila, M. E.; Xian, Lede; Cahangirov, S.; Rubio Secades, Angel; Le Lay, G. (IOP Publishing, 2014-09-09)
      We have grown an atom-thin, ordered, two-dimensional multi-phase film in situ through germanium molecular beam epitaxy using a gold (111) surface as a substrate. Its growth is similar to the formation of silicene layers ...
    • Thumbnail

      Giant diamagnetism of gold nanorods 

      Hernando, A.; Ayuela Fernández, Andrés; Crespo, P.; Echenique Landiribar, Pedro Miguel (IOP Publishing, 2014-07-30)
      The presence of giant diamagnetism in Au nanorods, NRs, is shown to be a possible consequence of field induced currents in the surface electrons. The distance, Delta , between quantum surface energy levels has been calculated ...
    • Thumbnail

      Hartle's model within the general theory of perturbatiye matchings: the change in mass 

      Reina Valdemoros, Borja; Vera Jménez, Raúl (IOP Publishing, 2015)
      Hartle's model provides the most widely used analytic framework to describe isolated compact bodies rotating slowly in equilibrium up to second order in perturbations in the context of General Relativity. Apart from some ...
    • Thumbnail

      Helmholtz Fermi surface harmonics: an efficient approach for treating anisotropic problems involving Fermi surface integrals 

      Eiguren Goyenechea, Asier; García de Gurtubay Galligo, Idoia (IOP Publishing, 2014-06-09)
      We present a new efficient numerical approach for representing anisotropic physical quantities and/or matrix elements defined on the Fermi surface (FS) of metallic materials. The method introduces a set of numerically ...
    • Thumbnail

      Interface electronics for an RF resonance-based displacement sensor 

      Asua Uriarte, Estibaliz; Echevarría Ecenarro, Víctor; García Arribas, Alfredo; Feutchwanger Morales, Jorge; Portilla Rubín, Joaquín; Lucas, J. (IOP Publishing LTD, 2013)
      We propose, design, and test an electronic interface for a new standalone, affordable and compact displacement transducer based on resonant cavities. The operation of the interface establishes a self-resonance in the ...
    • Thumbnail

      Is General Relativity a simplified theory? 

      Rivas Pérez, Martín (IOP Publishing, 2013)
      Gravity is understood as a geometrization of spacetime. But spacetime is also the manifold of the boundary values of the spinless point particle in a variational approach. Since all known matter, baryons, leptons and gauge ...
    • Thumbnail

      Long-lived oscillatory incoherent electron dynamics in molecules: trans-polyacetylene oligomers 

      Franco, Ignacio; Rubio Secades, Angel; Brumer, Paul (IOP Publishing, 2013-04)
      We identify an intriguing feature of the electron-vibrational dynamics of molecular systems via a computational examination of trans-polyacetylene oligomers. Here, via the vibronic interactions, the decay of an electron ...
    • Thumbnail

      Magnetization reversal and exchange bias effects in hard/soft ferromagnetic bilayers with orthogonal anisotropies 

      Navas Otero, David; Torrejón, J.; Béron, F.; Redondo Esteban, Carolina; Batallan, F.; Toperverg, B. P.; Devishvili, A.; Sierra Izquierdo, Borja; Castaño Almendral, Fernando; Pirota, K. R; Ross, C. A (IOP Publishing LTD, 2012-11-02)
      The magnetization reversal processes are discussed for exchange-coupled ferromagnetic hard/soft bilayers made from Co0.66Cr0.22Pt0.12 (10 and 20 nm)/Ni (from 0 to 40 nm) films with out-of-plane and in-plane magnetic easy ...
    • Thumbnail

      Metallic thin fi lms on stepped surfaces: lateral scattering of quantum well states 

      Schiller, F.; Abd El-Fattah, Z. M.; Schirone, S.; Lobo Checa, Jorge; Urdanpilleta Landaribar, Marta; Ruiz-Osés, M.; Cordón Velaz, Javier; Corso, M.; Sánchez-Portal, D.; Mugarza, A.; Ortega Conejero, José Enrique (IOP Publishing, 2014-12-10)
      Quantum well states of Ag films grown on stepped Au(111) surfaces are shown to undergo lateral scattering, in analogy with surface states of vicinal Ag(111). Applying angle resolved photoemission spectroscopy we observe ...
    • Thumbnail

      Microwave absorption properties of permalloy nanodots in the vortex and quasi-uniform magnetization states 

      Gusliyenko, Kostyantyn; Kakazei, G. N.; Kobljanskyj, Yu V.; Melkov, G. A.; Novosad, V.; Slavin, A. N. (IOP Publishing, 2014-06-19)
      When the in-plane bias magnetic field acting on a flat circular magnetic dot is smaller than the saturation field, there are two stable competing magnetization configurations of the dot: the vortex and the quasi-uniform ...
    • Thumbnail

      Occupational exposure to nano-TiO2 in the life cycle steps of new depollutant mortars used in construction 

      Vaquero, C.; Gelarza, N.; López de Ipiña, J. L.; Gutiérrez-Cañas Mateo, Cristina; Múgica Mendiola, Idoia; Aragón, G.; Jaen, M.; Pina, R.; Larraza, I.; Esteban-Cubillo, A.; Thompson, D.; Pui, D. Y. H. (IOP Publishing, 2015)
      The present work is focused on the measurement of workers exposure to nano-TiO2 in the life cycle steps of depollutant mortars. It has been done in the framework of the SCAFFOLD project, which aims at the management of ...
    • Thumbnail

      One-dimensional potential for image-potential states on graphene 

      De Andres, P. L.; Echenique Landiribar, Pedro Miguel; Niesner, D.; Fauster, Th.; Rivacoba Ochoa, Alberto Luis (IOP Publishing, 2014-02-05)
      In the framework of dielectric theory, the static non-local self-energy of an electron near an ultra-thin polarizable layer has been calculated and applied to study binding energies of image-potential states near free-standing ...
    • Thumbnail

      Optimally robust shortcuts to population inversion in two-level quantum systems 

      Ruschhaupt, A.; Chen, Xi; Alonso, D.; Muga Francisco, Juan Gonzalo (IOP Publishing LTD, 2012-09-21)
      We examine the stability versus different types of perturbations of recently proposed shortcuts to adiabaticity to speed up the population inversion of a two-level quantum system. We find the optimally robust processes by ...
    • Thumbnail

      Optimization of solution-processed oligothiophene:fullerene based organic solar cells by using solvent additives 

      Schulz, Gisela L.; Urdanpilleta Landaribar, Marta; Fitzner, Roland; Brier, Eduard; Mena Osteritz, Elena; Reinold, Egon; Baeuerle, Peter (Beilstein Institut, 2013-10)
      The optimization of solution-processed organic bulk-heterojunction solar cells with the acceptor-substituted quinquethiophene DCV5T-Bu-4 as donor in conjunction with PC61BM as acceptor is described. Power conversion ...
    • Thumbnail

      Permutationally invariant state reconstruction 

      Moroder, Tobias; Hyllus, Philipp; Tóth, Géza; Schwemmer, Christian; Niggebaum, Alexander; Gaile, Stefanie; Guehne, Otfried; Weinfurter, Harald (IOP Publishing, 2012-10)
      Feasible tomography schemes for large particle numbers must possess, besides an appropriate data acquisition protocol, an efficient way to reconstruct the density operator from the observed finite data set. Since state ...
    • Thumbnail

      Quantum ricochets: surface capture, release and energy loss of fast ions hitting a polar surface at grazing incidence 

      Lucas, A. A.; Sunjic, M.; Benedek, G.; Echenique Landiribar, Pedro Miguel (IOP Publishing, 2014-06-09)
      A diffraction mechanism is proposed for the capture, multiple bouncing and final escape of a fast ion (keV) impinging on the surface of a polarizable material at grazing incidence. Capture and escape are effected by elastic ...