1,262 research outputs found

    New strategy, new accountability? The European Central Bank and the European Parliament after the strategy review

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    A striking asymmetry defines the European Central Bank (ECB)’s approach to democratic accountability. Although the post-2008 era saw the ECB move dramatically beyond the narrow role envisaged for it by the 1992 Maastricht Treaty, the central bank has continued to hew closely to its scarce accountability provisions.This article documents the much more complex and discretionary nature of today’s ECB policymaking by comparing the frameworks informing Governing Council deliberations according to the 1998, 2003 and 2021 strategies. It shows that the transformation of the ECB’s monetary policy strategy has not been matched with enhanced accountability arrangements between the ECB and the European Parliament. The article concludes with ambitious, but concrete policy proposals – both in substance and form – for new ways of informing the public about monetary policy, instruments to improve accountability and coordinating monetary policy with other European policymakers

    Combined Electroweak Analysis

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    Recent developments in the measurement of precision electroweak measurements are summarised, notably new results on the mass of the top quark and mass and width of the W boson. Predictions of the Standard Model are compared to the experimental results which are used to constrain the input parameters of the Standard Model, in particular the mass of the Higgs boson. The agreement between measurements and expectations from theory is discussed. Invited talk presented at the EPS HEP 2007 conference Manchester, England, July 19th to 25th, 2007Comment: 7 pages and 6 figure

    Phonon-induced dephasing of localized optical excitations

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    The dynamics of strongly localized optical excitations in semiconductors is studied including electron-phonon interaction. The coupled microscopic equations of motion for the interband polarization and the carrier distribution functions contain coherent and incoherent contributions. While the coherent part is solved through direct numerical integration, the incoherent one is treated by means of a generalized Monte Carlo simulation. The approach is illustrated for a simple model system. The temperature and excitation energy dependence of the optical dephasing rate is analyzed and the results are compared to those of alternative approaches

    Polyply:A python suite for facilitating simulations of macromolecules and nanomaterials

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    Molecular dynamics simulations play an increasingly important role in the rational design of (nano)-materials and in the study of biomacromolecules. However, generating input files and realistic starting coordinates for these simulations is a major bottleneck, especially for high throughput protocols and for complex multi-component systems. To eliminate this bottleneck, we present the polyply software suite that provides 1) a multi-scale graph matching algorithm designed to generate parameters quickly and for arbitrarily complex polymeric topologies, and 2) a generic multi-scale random walk protocol capable of setting up complex systems efficiently and independent of the target force-field or model resolution. We benchmark quality and performance of the approach by creating realistic coordinates for polymer melt simulations, single-stranded as well as circular single-stranded DNA. We further demonstrate the power of our approach by setting up a microphase-separated block copolymer system, and by generating a liquid-liquid phase separated system inside a lipid vesicle

    Conformally Einstein Products and Nearly K\"ahler Manifolds

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    In the first part of this note we study compact Riemannian manifolds (M,g) whose Riemannian product with R is conformally Einstein. We then consider compact 6--dimensional almost Hermitian manifolds of type W_1+W_4 in the Gray--Hervella classification admitting a parallel vector field and show that (under some regularity assumption) they are obtained as mapping tori of isometries of compact Sasaki-Einstein 5-dimensional manifolds. In particular, we obtain examples of inhomogeneous locally (non-globally) conformal nearly K\"ahler compact manifolds

    Electroweak corrections to Higgs production through ZZ fusion at the linear collider

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    We present the full order alpha electroweak radiative corrections to e+e- -> e+e-H. The computation is performed with the help of GRACE-loop. The extraction of the full QED corrections is performed, these are quite large at threshold. The genuine weak corrections, for the linear collider energies, when expressed in the G_mu scheme are of order -2 to -4 for Higgs masses preferred by the latest precision data. We also extract the m_t^2 type corrections and make a comparison with the weak corrections for the process e+e- ->nu nu H.Comment: 16 pages and 6 figure

    Full one-loop electroweak radiative corrections to single Higgs production in e+ e-

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    We present the full O(α){{\cal O}}(\alpha) electroweak radiative corrections to single Higgs production in \epemt. This takes into account the full one-loop corrections as well as the effects of hard photon radiation. We include both the fusion and Higgs-strahlung processes. The computation is performed with the help of {\tt GRACE-loop} where we have implemented a generalised non-linear gauge fixing condition. The latter includes 5 gauge parameters that can be used for checks on our results. Besides the UV, IR finiteness and gauge parameter independence checks it proves also powerful to test our implementation of the 5-point function. We find that for a 500GeV machine and a light Higgs of mass 150GeV, the total O(α){{\cal O}}(\alpha) correction is small when the results are expressed in terms of αQED\alpha_{{\rm QED}}. The total correction decreases slightly for higher energies. For moderate centre of mass energies the total O(α){{\cal O}}(\alpha) decreases as the Higgs mass increases, reaching -10% for MH=350M_H=350GeV and s=500\sqrt{s}=500GeV. In order to quantify the genuine weak corrections we have subtracted the universal virtual and bremsstrahlung correction from the full O(α){{\cal O}}(\alpha). We find, for MH=150M_H=150GeV, a weak correction slowly decreasing from -2% to -4% as the energy increases from s=300\sqrt{s}=300GeV to s=1\sqrt{s}=1TeV after expressing the tree-level results in terms of GμG_\muComment: 16 pages, 3 figures. Only correction is a reference to a web-pag

    Nonequilibrium relaxation and scaling properties of the two-dimensional Coulomb glass in the aging regime

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    We employ Monte Carlo simulations to investigate the two-time density autocorrelation function for the two-dimensional Coulomb glass. We find that the nonequilibrium relaxation properties of this highly correlated disordered system can be described by a full aging scaling ansatz. The scaling exponents are non-universal, and depend on temperature and charge density.Comment: 6 pages, 3 figures included; revised version: corrected exponents, and some additional explanations and references added; to appear in EP

    History-dependent relaxation and the energy scale of correlation in the Electron-Glass

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    We present an experimental study of the energy-relaxation in Anderson-insulating indium-oxide films excited far from equilibrium. In particular, we focus on the effects of history on the relaxation of the excess conductance dG. The natural relaxation law of dG is logarithmic, namely dG=-log(t). This may be observed over more than five decades following, for example, cool-quenching the sample from high temperatures. On the other hand, when the system is excited from a state S_{o} in which it has not fully reached equilibrium to a state S_{n}, the ensuing relaxation law is logarithmic only over time t shorter than the time t_{w} it spent in S_{o}. For times t>t_{w} dG(t) show systematic deviation from the logarithmic dependence. It was previously shown that when the energy imparted to the system in the excitation process is small, this leads to dG=P(t/t_{w}) (simple-aging). Here we test the conjecture that `simple-aging' is related to a symmetry in the relaxation dynamics in S_{o} and S_{n}. This is done by using a new experimental procedure that is more sensitive to deviations in the relaxation dynamics. It is shown that simple-aging may still be obeyed (albeit with a modified P(t/t_{w})) even when the symmetry of relaxation in S_{o} and S_{n} is perturbed by a certain degree. The implications of these findings to the question of aging, and the energy scale associated with correlations are discussed

    ee4fgamma, A program for e+e- -> 4f, 4fgamma with nonzero fermion masses

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    A computer program ee4fgamma for calculating cross sections of any four fermion final state of e+e--annihilation at high energy and the corresponding bremsstrahlung reaction that is possible in the framework of the Standard Model is presented. As the fermion masses are arbitrary, the cross sections can be computed without any collinear cut, the on-shell top quark production can be studied and the Higgs boson exchange can be incorporated in a consistent way. The program can be used as a Monte Carlo generator of unweighted events as well.Comment: 20 pages; version published in Computer Physics Communication
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