52,314 research outputs found

    Reconstructing the geometric structure of a Riemannian symmetric space from its Satake diagram

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    The local geometry of a Riemannian symmetric space is described completely by the Riemannian metric and the Riemannian curvature tensor of the space. In the present article I describe how to compute these tensors for any Riemannian symmetric space from the Satake diagram, in a way that is suited for the use with computer algebra systems. As an example application, the totally geodesic submanifolds of the Riemannian symmetric space SU(3)/SO(3) are classified. The submission also contains an example implementation of the algorithms and formulas of the paper as a package for Maple 10, the technical documentation for this implementation, and a worksheet carrying out the computations for the space SU(3)/SO(3) used in the proof of Proposition 6.1 of the paper.Comment: 23 pages, also contains two Maple worksheets and technical documentatio

    NMR Measurements of Power-Law Behavior in the Spin-Wave and Critical Regions of Ferromagnetic EuO

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    Precision continuous-wave NMR measurements have been carried out over the entire magnetization curve of EuO and are presented in tabular form. Two very closely spaced resonances are observed and are attributed to domain and domain-wall signals. Both of the signals are useful for analysis in the spin-wave region. Only the domain signal is measurable above ~50K. The latter is used for fitting Tc and the critical exponent beta. The critical-region fits agree with previous measurements, within experimental error. The low-temperature data exhibit a clear-cut T^2 behavior, at variance with the expectations of conventional spin-wave theory. This result is discussed in relation to two semi-empirical spin-wave schemes, one formulated by N. Bykovetz, and one by U. Koebler. The NMR signal at 4.2K gives no indication of a quadrupole splitting, in contradiction to the interpretation of several previous spin-echo NMR spectra observed in EuO. This issue remains unresolved.Comment: 3 pages, 2 figures, 3 tables. in Proceedings of the 11TH Joint MMM-Intermag Conference, Washington, DC, 201

    Predictions for the First Parker Solar Probe Encounter

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    We examine Alfv\'en Wave Solar atmosphere Model (AWSoM) predictions of the first Parker Solar Probe (PSP) encounter. We focus on the 12-day closest approach centered on the 1st perihelion. AWSoM (van der Holst et al., 2014) allows us to interpret the PSP data in the context of coronal heating via Alfv\'en wave turbulence. The coronal heating and acceleration is addressed via outward-propagating low-frequency Alfv\'en waves that are partially reflected by Alfv\'en speed gradients. The nonlinear interaction of these counter-propagating waves results in a turbulent energy cascade. To apportion the wave dissipation to the electron and anisotropic proton temperatures, we employ the results of the theories of linear wave damping and nonlinear stochastic heating as described by Chandran et al. (2011). We find that during the first encounter, PSP was in close proximity to the heliospheric current sheet (HCS) and in the slow wind. PSP crossed the HCS two times, namely at 2018/11/03 UT 01:02 and 2018/11/08 UT 19:09 with perihelion occuring on the south of side of the HCS. We predict the plasma state along the PSP trajectory, which shows a dominant proton parallel temperature causing the plasma to be firehose unstable.Comment: 16 pages, 5 figures; accepted for publication in the Astrophysical Journal Letter

    Jet reconstruction and jet background classification with the ALICE experiment in PbPb collisions at the LHC

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    For a quantitative interpretation of reconstructed jet properties in heavy-ion collisions it is paramount to characterize the contribution from the underlying event and the influence of background fluctuations on the jet signal. In addition to the pure number fluctuations, region-to-region correlated background within one event can enhance or deplete locally the level of background and modify the jet energy. We show a first detailed assessment of background effects using different probes embedded into heavy-ion data and quantify their influence on the reconstructed jet spectrum.Comment: 4 pages, 2 figures, Proceedings for the XXII International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, Quark Matter 2011, Annec

    Addressing Alcohol\u27s Role in Campus Sexual Assault: A Toolkit by and for Prevention Specialists

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    This toolkit provides specific guidance on addressing alcohol\u27s role in campus sexual assault, centering Sexual Assault Prevention Specialists as the intended audience

    Tunneling Spectroscopy and Vortex Imaging in Boron-Doped Diamond

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    We present the first scanning tunneling spectroscopy study of single-crystalline boron doped diamond. The measurements were performed below 100 mK with a low temperature scanning tunneling microscope. The tunneling density of states displays a clear superconducting gap. The temperature evolution of the order parameter follows the weak coupling BCS law with Δ(0)/kBTc≃1.74\Delta(0)/k_B T_c \simeq 1.74. Vortex imaging at low magnetic field also reveals localized states inside the vortex core that are unexpected for such a dirty superconductor.Comment: 4 pages, 4 figures, replaced with revised versio
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