734 research outputs found

    Long-run Patterns of Labour Market Polarisation: Evidence from German Micro Data

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    The past four decades have witnessed dramatic changes in the structure of employment. In particular, the rapid increase in computational power has led to large-scale reductions in employment in jobs that can be described as intensive in routine tasks. These jobs have been shown to be concentrated in middle skill occupations. A large literature on labour market polarisation characterises and measures these processes at an aggregate level. How- ever to date there is little information regarding the individual worker adjustment processes related to routine- biased technological change. Using an administrative panel data set for Germany, we follow workers over an ex- tended period of time and provide evidence of both the short-term adjustment process and medium-run effects of routine task intensive job loss at an individual level. We initially demonstrate a marked, and steady, shift in em- ployment away from routine, middle-skill, occupations. In subsequent analysis, we demonstrate how exposure to jobs with higher routine task content is associated with a reduced likelihood of being in employment in both the short term (after one year) and medium term (five years). This employment penalty to routineness of work has increased over the past four decades. More generally, we demonstrate that routine task work is associated with reduced job stability and more likelihood of experiencing periods of unemployment. However, these negative ef- fects of routine work appear to be concentrated in increased employment to employment, and employment to unemployment transitions rather than longer periods of unemployment

    The Kiln Drying of Wood for Airplanes

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    This report is descriptive of various methods used in the kiln drying of woods for airplanes and gives the results of physical tests on different types of woods after being dried by the various kiln-drying methods

    Universality of weakly bound dimers and Efimov trimers close to Li-Cs Feshbach resonances

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    We study the interspecies scattering properties of ultracold Li-Cs mixtures in their two energetically lowest spin channels in the magnetic field range between 800 G and 1000 G. Close to two broad Feshbach resonances we create weakly bound LiCs dimers by radio-frequency association and measure the dependence of the binding energy on the external magnetic field strength. Based on the binding energies and complementary atom loss spectroscopy of three other Li-Cs s-wave Feshbach resonances we construct precise molecular singlet and triplet electronic ground state potentials using a coupled-channels calculation. We extract the Li-Cs interspecies scattering length as a function of the external field and obtain almost a ten-fold improvement in the precision of the values for the pole positions and widths of the s-wave Li-Cs Feshbach resonances as compared to our previous work [Pires \textit{et al.}, Phys. Rev. Lett. \textbf{112}, 250404 (2014)]. We discuss implications on the Efimov scenario and the universal geometric scaling for LiCsCs trimers

    Exciton Condensation and Perfect Coulomb Drag

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    Coulomb drag is a process whereby the repulsive interactions between electrons in spatially separated conductors enable a current flowing in one of the conductors to induce a voltage drop in the other. If the second conductor is part of a closed circuit, a net current will flow in that circuit. The drag current is typically much smaller than the drive current owing to the heavy screening of the Coulomb interaction. There are, however, rare situations in which strong electronic correlations exist between the two conductors. For example, bilayer two-dimensional electron systems can support an exciton condensate consisting of electrons in one layer tightly bound to holes in the other. One thus expects "perfect" drag; a transport current of electrons driven through one layer is accompanied by an equal one of holes in the other. (The electrical currents are therefore opposite in sign.) Here we demonstrate just this effect, taking care to ensure that the electron-hole pairs dominate the transport and that tunneling of charge between the layers is negligible.Comment: 12 pages, 4 figure

    Radio frequency association of heteronuclear Feshbach molecules

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    We present a detailed analysis of the production efficiency of weakly bound heteronuclear KRb-Feshbach molecules using radio frequency association in a harmonic trap. The efficiency was measured in a wide range of temperatures, binding energies and radio frequencies. A comprehensive analytical model is presented, explaining the observed asymmetric spectra and achieving good quantitative agreement with the measured production rates. This model provides a deep understanding of the molecule association process and paves the way for future experiments which rely on Feshbach molecules e.g. for the production of deeply bound molecules.Comment: 5 pages, 4 figure

    Exciton condensate at a total filling factor of 1 in Corbino 2D electron bilayers

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    Magneto-transport and drag measurements on a quasi-Corbino 2D electron bilayer at the systems total filling factor 1 (v_tot=1) reveal a drag voltage that is equal in magnitude to the drive voltage as soon as the two layers begin to form the expected v_tot=1 exciton condensate. The identity of both voltages remains present even at elevated temperatures of 0.25 K. The conductance in the current carrying layer vanishes only in the limit of strong coupling between the two layers and at T->0 K which suggests the presence of an excitonic circular current

    Analyzing Feshbach resonances -- A 6^6Li -133^{133}Cs case study

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    We provide a comprehensive comparison of a coupled channels calculation, the asymptotic bound state model (ABM), and the multichannel quantum defect theory (MQDT). Quantitative results for 6^6Li -133^{133}Cs are presented and compared to previously measured 6^6Li -133^{133}Cs Feshbach resonances (FRs) [M. Repp et al., Phys. Rev. A 87 010701(R) (2013)]. We demonstrate how the accuracy of the ABM can be stepwise improved by including magnetic dipole-dipole interactions and coupling to a non-dominant virtual state. We present a MQDT calculation, where magnetic dipole-dipole and second order spin-orbit interactions are included. A frame transformation formalism is introduced, which allows the assignment of measured FRs with only three parameters. All three models achieve a total rms error of < 1G on the observed FRs. We critically compare the different models in view of the accuracy for the description of FRs and the required input parameters for the calculations.Comment: 16 pages, 3 figures, 1 tabl
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