5,648 research outputs found

    Interaction of Saturn's magnetosphere and its moons: 3. Time variation of the Enceladus plume

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95380/1/jgra20677.pd

    Searching for Galactic White Dwarf Binaries in Mock LISA Data using an F-Statistic Template Bank

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    We describe an F-statistic search for continuous gravitational waves from galactic white-dwarf binaries in simulated LISA Data. Our search method employs a hierarchical template-grid based exploration of the parameter space. In the first stage, candidate sources are identified in searches using different simulated laser signal combinations (known as TDI variables). Since each source generates a primary maximum near its true "Doppler parameters" (intrinsic frequency and sky position) as well as numerous secondary maxima of the F-statistic in Doppler parameter space, a search for multiple sources needs to distinguish between true signals and secondary maxima associated with other, "louder" signals. Our method does this by applying a coincidence test to reject candidates which are not found at nearby parameter space positions in searches using each of the three TDI variables. For signals surviving the coincidence test, we perform a fully coherent search over a refined parameter grid to provide an accurate parameter estimation for the final candidates. Suitably tuned, the pipeline is able to extract 1989 true signals with only 5 false alarms. The use of the rigid adiabatic approximation allows recovery of signal parameters with errors comparable to statistical expectations, although there is still some systematic excess with respect to statistical errors expected from Gaussian noise. An experimental iterative pipeline with seven rounds of signal subtraction and re-analysis of the residuals allows us to increase the number of signals recovered to a total of 3419 with 29 false alarms.Comment: 29 pages, 11 figures; submitted to Classical and Quantum Gravit

    Inelastic X-ray scattering in correlated (Mott) insulators

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    We calculate the inelastic light scattering from X-rays, which allows the photon to transfer both energy and momentum to the strongly correlated charge excitations. We find that the charge transfer peak and the low energy peak both broaden and disperse through the Brillouin zone similar to what is seen in experiments in materials like Ca_2 Cu O_2 Cl_2.Comment: 5 pages Revtex4, 6 figure

    Nonlinear Optical Response Functions of Mott Insulators Based on Dynamical Mean Field Approximation

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    We investigate the nonlinear optical susceptibilities of Mott insulators with the dynamical mean field approximation. The two-photon absorption (TPA) and the third-harmonic generation (THG) spectra are calculated, and the classification by the types of coupling to external fields shows different behavior from conventional semiconductors. The direct transition terms are predominant both in the TPA and THG spectra, and the importance of taking all types of interaction with the external field into account is illustrated in connection with the THG spectrum and dcKerr effect. The dependence of the TPA and THG spectra on the Coulomb interaction indicate a scaling relation. We apply this relation to the quantitative evaluation and obtain results comparable to those of experiments.Comment: 14 pages, 12 figure

    Behaviour of three charged particles on a plane under perpendicular magnetic field

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    We consider the problem of three identical charged particles on a plane under a perpendicular magnetic field and interacting through Coulomb repulsion. This problem is treated within Taut's framework, in the limit of vanishing center of mass vector R0\vec{R} \to \vec{0}, which corresponds to the strong magnetic field limit, occuring for example in the Fractional Quantum Hall Effect. Using the solutions of the biconfluent Heun equation, we compute the eigenstates and show that there is two sets of solutions. The first one corresponds to a system of three independent anyons which have their angular momenta fixed by the value of the magnetic field and specified by a dimensionless parameter ClBl0C \simeq \frac{l_B}{l_0}, the ratio of lBl_B, the magnetic length, over l0l_0, the Bohr radius. This anyonic character, consistent with quantum mechanics of identical particles in two dimensions, is induced by competing physical forces. The second one corresponds to the case of the Landau problem when C0C \to 0. Finally we compare these states with the quantum Hall states and find that the Laughlin wave functions are special cases of our solutions under certains conditions.Comment: 15 pages, 3 figures, Accepeted in JP

    Microscopic Mechanism for Staggered Scalar Order in PrFe4P12

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    A microscopic model is proposed for the scalar order in PrFe4P12 where f2 crystalline electric field (CEF) singlet and triplet states interact with two conduction bands. By combining the dynamical mean-field theory and the continuous-time quantum Monte Carlo, we obtain an electronic order with staggered Kondo and CEF singlets with the total conduction number being unity per site. The ground state becomes semimetallic provided that the two conduction bands have different occupation numbers. This model naturally explains experimentally observed properties in the ordered phase of PrFe4P12 such as the scalar order parameter, temperature dependence of the resistivity, field-induced staggered moment, and inelastic features in neutron scattering. The Kondo effect plays an essential role for ordering, in strong contrast with ordinary magnetic orders by the RKKY interaction.Comment: 4 pages, 4figure

    Thermoelectrics Near the Mott Localization-Delocalization Transition

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    We give an overview on current status of the theoretical research on Thermoelectricity for correlated materials. We derive the theoretical formulas which become exact at low and high temperature and discuss the intermediate temperature results. In particular, we show that within Dynamical Mean Field Theory the low temperature sign of the thermopower is not necessary the same as in LDA, and that significant non-universality is expected due to strong correlations.Comment: appeared in "Properties and Applications of Thermoelectric Materials", Edited by V. Zlatic and A.C. Hewson, Springe

    Late widespread skeletal metastases from myxoid liposarcoma detected by MRI only

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    Background Myxoid liposarcoma is the second most commonly occurring sub-type of liposarcomas. In contrast to other soft tissue sarcomas, it is known to have a tendency to spread toward extrapulmonary sites, such as soft tissues, retroperitoneum, and the peritoneal surface. Bony spread, however, is not as common. Case presentation We report an unusual case of diffuse skeletal metastases from myxoid liposarcoma occurring 13 years after treatment of the primary tumour in the left lower limb. The skeletal spread of the disease was demonstrated on MRI only after other imaging modalities (plain radiography, CT and TC99 bone scans) had failed to detect these metastases. Conclusion MRI is an extremely sensitive and specific screening tool in the detection of skeletal involvement in these types of sarcomas, and therefore, should be a part of the staging proces

    Structure of the Jovian magnetodisk current sheet] initial Galileo observations

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    Abstract The ten!degree tilt of the Jovian magnetic dipole causes the magnetic equator to move back and forth across Jupiter|s rotational equator and the Galileo orbit that lies therein[ Beyond about 13 Jovian radii\ the equatorial current sheet thins and the magnetic structure changes from quasi!dipolar into magnetodisk!like with two regions of nearly radial but antiparallel magnetic _eld separated by a strong current layer[ The magnetic _eld at the center of the current sheet is very weak in this region[ Herein we examine the current sheet at radial distances from 13Ð44 Jovian radii[ We _nd that the magnetic structure very much resembles the structure seen at planetary magnetopause and tail current sheet crossings There is also transient or patchy reconnection in which short duration strong nor! mal components and fast~ows are seen "Russell and Elphic\ 0867#[ Steady!state reconnection has been con! _rmed only at the terrestrial magnetopause but evidence for transient reconnection has been found at Mercury "Russell and Walker\ 0874#^Earth "Russell and Elphic\ 0867# and Jupiter "Walker and Russell\ 0874#[ Finally\ there is apparently quiescent structure along the mag! netopause normal that seems not to lead to any dynami! cal consequences[ These structured\ but apparently quiescent\ normal components are seen at magnetopause crossings throughout the solar system "Huddleston et al [\ 0886#
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