40,618 research outputs found

    Critical temperature and Ginzburg region near a quantum critical point in two-dimensional metals

    Full text link
    We compute the transition temperature TcT_c and the Ginzburg temperature TGT_{\rm G} above TcT_c near a quantum critical point at the boundary of an ordered phase with a broken discrete symmetry in a two-dimensional metallic electron system. Our calculation is based on a renormalization group analysis of the Hertz action with a scalar order parameter. We provide analytic expressions for TcT_c and TGT_{\rm G} as a function of the non-thermal control parameter for the quantum phase transition, including logarithmic corrections. The Ginzburg regime between TcT_c and TGT_{\rm G} occupies a sizable part of the phase diagram.Comment: 5 pages, 1 figur

    A proof of factorization for B -> D pi

    Get PDF
    We prove that the matrix elements of four fermion operators mediating the decay B^0 -> D^+ \pi^- and B^- -> D^0 \pi^- factor into the product of a form factor describing the B -> D transition and a convolution of a short distance coefficient with the nonperturbative pion light-cone wave function. This is shown to all orders in alpha_s, up to corrections suppressed by factors of 1/mb, 1/mc, and 1/E_pi. It is not necessary to assume that the pion state is dominated by the q-qbar Fock state.Comment: 4 pages, 3 figs, PRL versio

    Sheepskin Effects in Japan

    Get PDF
    Using data for the 1990’s, this paper examines the role of sheepskin effects in the returns to education for Japan. Our estimation results indicate that sheepskin effects explain about 50% of the total returns to schooling. We further find that sheepskin effect are only important for workers in small firms with the size of these effects being similar to comparable estimates for the US. Finally, the estimated sheepskin effects are decreasing with firm tenure, in particular for small firms. These results could be explained by the particular recruitment system of large firms in Japan, which makes university diploma as a screening device unimportant for large firms.Returns to Education, Sheepskin Effects, Japan

    New multivariable capabilities of the INCA program

    Get PDF
    The INteractive Controls Analysis (INCA) program was developed at NASA's Goddard Space Flight Center to provide a user friendly, efficient environment for the design and analysis of control systems, specifically spacecraft control systems. Since its inception, INCA has found extensive use in the design, development, and analysis of control systems for spacecraft, instruments, robotics, and pointing systems. The (INCA) program was initially developed as a comprehensive classical design analysis tool for small and large order control systems. The latest version of INCA, expected to be released in February of 1990, was expanded to include the capability to perform multivariable controls analysis and design

    Correlations and contrasts in structural history and style between an Archaean greenstone belt and adjacent gneiss belt, NE Minnesota

    Get PDF
    An analysis of the deformation along the boundary between the Vermilion Granitic Complex (VGC) and the Vermilion district indicates that the two terranes have seen a similar deformation history since the earliest stages of folding in the area. Despite this common history, variations in structural style occur between the two terranes, such as the relative development of D sub 1 fabrics and D sub 2 shear zones, and these can be attributed to differences in the crustal levels of the two terranes during the deformation. Similarly, the local development of F sub 3 folds in the VGC, but not in the Vermilion district, is interpreted to be a result of later-D sub 2 pluton emplacement which was not significant at the level of exposure of ther Vermilion district

    Interface resistance of disordered magnetic multilayers

    Full text link
    We study the effect of interface disorder on the spin-dependent interface resistances of Co/Cu, Fe/Cr and Au/Ag multilayers using a newly developed method for calculating transmission matrices from first-principles. The efficient implementation using tight-binding linear-muffin-tin orbitals allows us to model interface disorder using large lateral supercells whereby specular and diffuse scattering are treated on an equal footing. Without introducing any free parameters, quantitative agreement with experiment is obtained. We predict that disorder {\it reduces} the majority-spin interface resistance of Fe/Cr(100) multilayers by a factor 3.Comment: 5 pages, 2 figures, submitted to PR

    Runtime Verification of Temporal Properties over Out-of-order Data Streams

    Full text link
    We present a monitoring approach for verifying systems at runtime. Our approach targets systems whose components communicate with the monitors over unreliable channels, where messages can be delayed or lost. In contrast to prior works, whose property specification languages are limited to propositional temporal logics, our approach handles an extension of the real-time logic MTL with freeze quantifiers for reasoning about data values. We present its underlying theory based on a new three-valued semantics that is well suited to soundly and completely reason online about event streams in the presence of message delay or loss. We also evaluate our approach experimentally. Our prototype implementation processes hundreds of events per second in settings where messages are received out of order.Comment: long version of the CAV 2017 pape
    corecore