47,981 research outputs found

    Properties of solutions of stochastic differential equations driven by the G-Brownian motion

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    In this paper, we study the differentiability of solutions of stochastic differential equations driven by the GG-Brownian motion with respect to the initial data and the parameter. In addition, the stability of solutions of stochastic differential equations driven by the GG-Brownian motion is obtained

    The motion, stability and breakup of a stretching liquid bridge with a receding contact line

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    The complex behavior of drop deposition on a hydrophobic surface is considered by looking at a model problem in which the evolution of a constant-volume liquid bridge is studied as the bridge is stretched. The bridge is pinned with a fixed diameter at the upper contact point, but the contact line at the lower attachment point is free to move on a smooth substrate. Experiments indicate that initially, as the bridge is stretched, the lower contact line slowly retreats inwards. However at a critical radius, the bridge becomes unstable, and the contact line accelerates dramatically, moving inwards very quickly. The bridge subsequently pinches off, and a small droplet is left on the substrate. A quasi-static analysis, using the Young-Laplace equation, is used to accurately predict the shape of the bridge during the initial bridge evolution, including the initial onset of the slow contact line retraction. A stability analysis is used to predict the onset of pinch-off, and a one-dimensional dynamical equation, coupled with a Tanner-law for the dynamic contact angle, is used to model the rapid pinch-off behavior. Excellent agreement between numerical predictions and experiments is found throughout the bridge evolution, and the importance of the dynamic contact line model is demonstrated.Comment: 37 pages, 12 figure

    Bose-Einstein Condensation with Entangled Order Parameter

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    We propose a practically accessible non-mean-field ground state of Bose-Einstein condensation (BEC), which occurs in an interspecies two-particle entangled state, and is thus described by an entangled order parameter. A suitably defined entanglement entropy is used as the characterization of the non-mean-field nature, and is found to persist in a wide parameter regime. The interspecies entanglement leads to novel interference terms in the dynamical equations governing the single particle orbital wavefunctions. Experimental feasibility and several methods of probe are discussed. We urge the study of multi-channel scattering between different species of atoms.Comment: V1: 5 pages, 4 figures. Accepted by Phys. Rev. Lett.; V2: A couple of very minor typos corrected, publishe

    Abundances in the Uranium-Rich Star CS 31082-001

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    The recent discovery by Cayrel et al. of U in CS 31082-001 along with Os and Ir at greatly enhanced abundances but with [Fe/H]=-2.9 strongly reinforces the argument that there are at least two kinds of SNII sources for r-nuclei. One source is the high-frequency H events responsible for heavy r-nuclei (A>135) but not Fe. The H-yields calculated from data on other ultra-metal-poor stars and the sun provide a template for quantitatively predicting the abundances of all other r-elements. In CS 31082-001 these should show a significant deficiency at A<135 relative to the solar r-pattern. It is proposed that CS 31082-001 should have had a companion that exploded as an SNII H event. If the binary survived the explosion, this star should now have a compact companion, most likely a stellar-mass black hole. Comparison of abundance data with predicted values and a search for a compact companion should provide a stringent test of the proposed r-process model. The U-Th age determined by Cayrel et al. for CS 31082-001 is, to within substantial uncertainties, in accord with the r-process age determined from solar system data. The time gap between Big Bang and onset of normal star formation only allows r-process chronometers to provide a lower limit on the age of the universe.Comment: 5 pages, 1 figur

    r-Process Nucleosynthesis in Shocked Surface Layers of O-Ne-Mg Cores

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    We demonstrate that rapid expansion of the shocked surface layers of an O-Ne-Mg core following its collapse can result in r-process nucleosynthesis. As the supernova shock accelerates through these layers, it makes them expand so rapidly that free nucleons remain in disequilibrium with alpha-particles throughout most of the expansion. This allows heavy r-process isotopes including the actinides to form in spite of the very low initial neutron excess of the matter. We estimate that yields of heavy r-process nuclei from this site may be sufficient to explain the Galactic inventory of these isotopes.Comment: 11 pages, 1 figure, to appear in the Astrophysical Journal Letter

    Asymptotic behavior of the least common multiple of consecutive arithmetic progression terms

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    Let ll and mm be two integers with l>m0l>m\ge 0, and let aa and bb be integers with a1a\ge 1 and a+b1a+b\ge 1. In this paper, we prove that loglcmmn<iln{ai+b}=An+o(n)\log {\rm lcm}_{mn<i\le ln}\{ai+b\} =An+o(n), where AA is a constant depending on l,ml, m and aa.Comment: 8 pages. To appear in Archiv der Mathemati
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