4,579 research outputs found

    Wideband dual sphere detector of gravitational waves

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    We present the concept of a sensitive AND broadband resonant mass gravitational wave detector. A massive sphere is suspended inside a second hollow one. Short, high-finesse Fabry-Perot optical cavities read out the differential displacements of the two spheres as their quadrupole modes are excited. At cryogenic temperatures one approaches the Standard Quantum Limit for broadband operation with reasonable choices for the cavity finesses and the intracavity light power. A molybdenum detector of overall size of 2 m, would reach spectral strain sensitivities of 2x10^-23/Sqrt{Hz} between 1000 Hz and 3000 Hz.Comment: 4 pages, 3 figures. Changed content. To appear in Phys. Rev. Let

    Symbiotic Bright Solitary Wave Solutions of Coupled Nonlinear Schrodinger Equations

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    Conventionally, bright solitary wave solutions can be obtained in self-focusing nonlinear Schrodinger equations with attractive self-interaction. However, when self-interaction becomes repulsive, it seems impossible to have bright solitary wave solution. Here we show that there exists symbiotic bright solitary wave solution of coupled nonlinear Schrodinger equations with repulsive self-interaction but strongly attractive interspecies interaction. For such coupled nonlinear Schrodinger equations in two and three dimensional domains, we prove the existence of least energy solutions and study the location and configuration of symbiotic bright solitons. We use Nehari's manifold to construct least energy solutions and derive their asymptotic behaviors by some techniques of singular perturbation problems.Comment: to appear in Nonlinearit

    Multipulse phases in k-mixtures of Bose-Einstein condensates

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    For a competitive system of k coupled nonlinear Schroedinger equations we prove the existence, when the competition parameter is large, of positive radial solutions on R^N. We show that, when the competition parameter goes to infinity, the profile of each component separates, in many pulses, from the others. Moreover, we can prescribe the location of such pulses in terms of the oscillations of the changing-sign solutions of the scalar nonlinear Schroedinger equation. Within an Hartree-Fock approximation, this provides a theoretical indication of phase separation into many nodal domains for the k-mixtures of Bose-Einstein condensates.Comment: 21 page

    Effectiveness and safety of robotic radiosurgery for optic nerve sheath meningiomas: A single institution series

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    The role of robotic radiosurgery (RRS) in the treatment of optic nerve sheath meningiomas (ONSM) remains controversial and it is only performed in specialized institutions due to tight dose constraints. We evaluated the effectiveness and safety of RRS in the management of ONSM. Twenty-five patients with 27 ONSM lesions who underwent RRS using the Cyberknife (CK) system were retrospectively analyzed (median age, 47.9 years; 84.0% women). Multisession RRS was used with 4–5 fractions with a cumulative dose of 20.0–25.0 Gy in 84.0% of patients and a single fraction at a dose of 14.0–15.0 Gy in 16% of patients. Prior to RRS, seven (28%) patients experienced blindness on the lesion side. In those patients with preserved vision prior to radiosurgery, the visual acuity remained the same in 90.0% and improved in 10.0% of the patients. Overall local tumor control was 96.0% (mean follow-up period; 37.4 ± 27.2 months). Neither patient age, previous surgery, or the period from the initial diagnosis to RRS showed a dependency on visual acuity before or after radiosurgery. RRS is a safe and effective treatment for the management of ONSM. Hypofractionation of radiosurgery in patients with preserved vision before CK treatment results in stable or improved vision

    Normal scaling in globally conserved interface-controlled coarsening of fractal clusters

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    Globally conserved interface-controlled coarsening of fractal clusters exhibits dynamic scale invariance and normal scaling. This is demonstrated by a numerical solution of the Ginzburg-Landau equation with a global conservation law. The sharp-interface limit of this equation is volume preserving motion by mean curvature. The scaled form of the correlation function has a power-law tail accommodating the fractal initial condition. The coarsening length exhibits normal scaling with time. Finally, shrinking of the fractal clusters with time is observed. The difference between global and local conservation is discussed.Comment: 4 pages, 3 eps figure

    Weighted azimuthal asymmetries in a diquark spectator model

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    We analytically calculate weighted azimuthal asymmetries in semi-inclusive lepton-nucleon deep-inelastic scattering and Drell-Yan processes, using transverse-momentum-dependent partonic densities obtained in a diquark spectator model. We compare the asymmetries with available preliminary experimental data, in particular for the Collins and the Sivers effect. We make predictions for other cases of interest in running and planned experiments.Comment: 21 pages, 13 (multiple) figures in eps format, RevTeX

    Positive Least Energy Solutions and Phase Separation for Coupled Schrodinger Equations with Critical Exponent: Higher Dimensional Case

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    We study the following nonlinear Schr\"{o}dinger system which is related to Bose-Einstein condensate: {displaymath} {cases}-\Delta u +\la_1 u = \mu_1 u^{2^\ast-1}+\beta u^{\frac{2^\ast}{2}-1}v^{\frac{2^\ast}{2}}, \quad x\in \Omega, -\Delta v +\la_2 v =\mu_2 v^{2^\ast-1}+\beta v^{\frac{2^\ast}{2}-1} u^{\frac{2^\ast}{2}}, \quad x\in \om, u\ge 0, v\ge 0 \,\,\hbox{in \om},\quad u=v=0 \,\,\hbox{on \partial\om}.{cases}{displaymath} Here \om\subset \R^N is a smooth bounded domain, 2∗:=2NN−22^\ast:=\frac{2N}{N-2} is the Sobolev critical exponent, -\la_1(\om)0 and ÎČ≠0\beta\neq 0, where \lambda_1(\om) is the first eigenvalue of −Δ-\Delta with the Dirichlet boundary condition. When \bb=0, this is just the well-known Brezis-Nirenberg problem. The special case N=4 was studied by the authors in (Arch. Ration. Mech. Anal. 205: 515-551, 2012). In this paper we consider {\it the higher dimensional case N≄5N\ge 5}. It is interesting that we can prove the existence of a positive least energy solution (u_\bb, v_\bb) {\it for any ÎČ≠0\beta\neq 0} (which can not hold in the special case N=4). We also study the limit behavior of (u_\bb, v_\bb) as ÎČ→−∞\beta\to -\infty and phase separation is expected. In particular, u_\bb-v_\bb will converge to {\it sign-changing solutions} of the Brezis-Nirenberg problem, provided N≄6N\ge 6. In case \la_1=\la_2, the classification of the least energy solutions is also studied. It turns out that some quite different phenomena appear comparing to the special case N=4.Comment: 48 pages. This is a revised version of arXiv:1209.2522v1 [math.AP

    Single - and double energy swift and slow heavy ion irradiated optical waveguides in Er: Tungstene-Tellurite glass and BGO for telecom applications

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    The fabrication of broadband amplifiers in wavelength division multiplexing (WDM) around 1.55 m, as they exhibit large stimulated cross sections and broad emission bandwidth. Bi4Ge3O12 (eultine type BGO) - well known scintillator material, also a rare-earth host material, photorefractive waveguides produced in it only using light ions in the past. Recently: MeV N+ ions and swift O5+ and C5+ ions, too*. Bi12GeO20 (sillenite type BGO) - high photoconductivity and photorefractive sensitivity in the visible and NIR good candidate for real-time holography and optical phase conjugation, photorefractive waveguides produced in it only using light ions. No previous attempts of ion beam fabrication of waveguides in it

    Quadratic solitons as nonlocal solitons

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    We show that quadratic solitons are equivalent to solitons of a nonlocal Kerr medium. This provides new physical insight into the properties of quadratic solitons, often believed to be equivalent to solitons of an effective saturable Kerr medium. The nonlocal analogy also allows for novel analytical solutions and the prediction of novel bound states of quadratic solitons.Comment: 4 pages, 3 figure
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