3,716 research outputs found

    Many-body quantum coherence and interaction blockade in Josephson-linked Bose-Einstein condensates

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    We study many-body quantum coherence and interaction blockade in two Josephson-linked Bose-Einstein condensates. We introduce universal operators for characterizing many-body coherence without limitations on the system symmetry and total particle number NN. We reproduce the results for both coherence fluctuations and number squeezing in {\em symmetric} systems of large NN, and reveal several peculiar phenomena that may occur in {\em asymmetric} systems and systems of small NN. For asymmetric systems, we show that, due to an interplay between asymmetry and inter-particle interaction, the coherence fluctuations are suppressed dramatically when EC/EJ1|E_{C}/E_{J}|\ll 1, and both {\it resonant tunneling} and {\it interaction blockade} take place for large values of EC/EJ|E_{C}/E_{J}|, where ECE_C and EJE_J are the interaction and tunneling energies, respectively. We emphasize that the resonant tunneling and interaction blockade may allow creating single-atom devices with promising technology applications. We demonstrate that for the systems at finite temperatures the formation of self-trapped states causes an anomalous behavior.Comment: 6 pages, 5 figures, accepted for publication in EPL (Europhysics Letters

    Soliton transverse instabilities in nonlocal nonlinear media

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    We analyze the transverse instabilities of spatial bright solitons in nonlocal nonlinear media, both analytically and numerically. We demonstrate that the nonlocal nonlinear response leads to a dramatic suppression of the transverse instability of the soliton stripes, and we derive the asymptotic expressions for the instability growth rate in both short- and long-wave approximations.Comment: 3 pages, 3 figure

    From Laser Induced Line Narrowing To Electromagnetically Induced Transparency: Closed System Analysis

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    Laser induced line narrowing effect, discovered more than thirty years ago, can also be applied to recent studies in high resolution spectroscopy based on electromagnetically induced transparency. In this paper we first present a general form of the transmission width of electromagnetically induced transparency in a homogeneously broadened medium. We then analyze a Doppler broadened medium by using a Lorentzian function as the atomic velocity distribution. The dependence of the transmission linewidth on the driving field intensity is discussed and compared to the laser induced line narrowing effect. This dependence can be characterized by a parameter which can be regarded as ``the degree of optical pumping''.Comment: 8 pages, 5 figure

    Blooming Numbers: Interactive Visualization in Cultural Contexts Based on Numbers

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    The Blooming Numbers is an application based on the web for the purpose of visualizing the relationships between cultural contexts and the preference of numbers in interactive and dynamic ways. People from different cultural background have varying opinions about numbers. My basic idea was to explore effective visualization based on this interesting observation. My thesis project provides an interactive application to convey a huge amount of information about numbers, as well as a fun experience with an art work generated with diverse data provided by the users

    New parametrization for differences between plasma kinetic codes

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    Validation and verification of plasma kinetics codes requires the development of quantitative methods and techniques for code comparisons. We describe two parameters that can be used for characterization of differences between such codes. It is shown that these parameters, which are determined from the most general results of kinetic codes, can provide important information on the differences between the basic rate coefficients employed. Application of this method is illustrated by comparisons of some results from the 3rd NLTE Code Comparison Workshop for carbon, germanium, and gold plasmas.Comment: Submitted to High Energy Density Physics, 12 pages, 2 figure

    Squeezing and entanglement of matter-wave gap solitons

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    We study quantum squeezing and entanglement of gap solitons in a Bose-Einstein condensate loaded into a one-dimensional optical lattice. By employing a linearized quantum theory we find that quantum noise squeezing of gap solitons, produced during their evolution, is enhanced compared with the atomic solitons in a lattice-free case due to intra-soliton structure of quantum correlations induced by the Bragg scattering in the periodic potential. We also show that nonlinear interaction of gap solitons in dynamically stable bound states can produce strong soliton entanglement.Comment: 4 pages, 5 figure