746 research outputs found

    Nonclassical dynamics of Bose condensates in an optical lattice in the superfluid regime

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    A condensate in an optical lattice, prepared in the ground state of the superfluid regime, is stimulated first by suddenly increasing the optical lattice amplitude and then, after a waiting time, by abruptly decreasing this amplitude to its initial value. Thus the system is first taken to the Mott regime and then back to the initial superfluid regime. We show that, as a consequence of this nonadiabatic process, the system falls into a configuration far from equilibrium whose superfluid order parameter is described in terms of a particular superposition of Glauber coherent states that we derive. We also show that the classical equations of motion describing the time evolution of this system are inequivalent to the standard discrete nonlinear Schreodinger equations. By numerically integrating such equations with several initial conditions, we show that the system loses coherence, becoming insulating.Comment: 5 pages, 4 figure

    Quantum correlations of two optical fields close to electromagnetically induced transparency

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    We show that three-level atoms excited by two cavity modes in a Λ\Lambda configuration close to electromagnetically induced transparency can produce strongly squeezed bright beams or correlated beams which can be used for quantum non demolition measurements. The input intensity is the experimental "knob" for tuning the system into a squeezer or a quantum non demolition device. The quantum correlations become ideal at a critical point characterized by the appearance of a switching behavior in the mean fields intensities. Our predictions, based on a realistic fully quantum 3-level model including cavity losses and spontaneous emission, allow direct comparison with future experiments.Comment: 4 pages, 5 figure

    Squeezing and entangling nuclear spins in helium 3

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    We present a realistic model for transferring the squeezing or the entanglement of optical field modes to the collective ground state nuclear spin of 3^3He using metastability exchange collisions. We discuss in detail the requirements for obtaining good quantum state transfer efficiency and study the possibility to readout the nuclear spin state optically

    Evolution of the macroscopically entangled states in optical lattices

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    We consider dynamics of boson condensates in finite optical lattices under a slow external perturbation which brings the system to the unstable equilibrium. It is shown that quantum fluctuations drive the condensate into the maximally entangled state. We argue that the truncated Wigner approximation being a natural generalization of the Gross-Pitaevskii classical equations of motion is adequate to correctly describe the time evolution including both collapse and revival of the condensate.Comment: 14 pages, 10 figures, Discussion of reversibility of entanglement is adde

    Genuine phase diffusion of a Bose-Einstein condensate in the microcanonical ensemble: A classical field study

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    Within the classical field model, we find that the phase of a Bose-Einstein condensate undergoes a true diffusive motion in the microcanonical ensemble, the variance of the condensate phase change between time zero and time tt growing linearly in tt. The phase diffusion coefficient obeys a simple scaling law in the double thermodynamic and Bogoliubov limit. We construct an approximate calculation of the diffusion coefficient, in fair agreement with the numerical results over the considered temperature range, and we extend this approximate calculation to the quantum field.Comment: 9 pages, 6 figure

    Non-diffusive phase spreading of a Bose-Einstein condensate at finite temperature

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    We show that the phase of a condensate in a finite temperature gas spreads linearly in time at long times rather than in a diffusive way. This result is supported by classical field simulations, and analytical calculations which are generalized to the quantum case under the assumption of quantum ergodicity in the system. This super-diffusive behavior is intimately related to conservation of energy during the free evolution of the system and to fluctuations of energy in the prepared initial state.Comment: 16 pages, 7 figure

    Entanglement properties of degenerate four-wave mixing of matter-waves in a periodic potential

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    In a recent experiment Campbell et al. [Phys. Rev. Lett. 96, 020406 (2006)] observed degenerate four-wave mixing of matter-waves in a one-dimensional optical lattice, a process with potential for generating entanglement among atoms. We analyse the essential quantum features of the experiment to show that entanglement is created between the quadratures of the two scattered atomic clouds and is a true many-body (rather than two-body) effect. We demonstrate a significant violation of entanglement inequalities that is robust to a moderate level of coherent seeding. The system is thus a promising candididate for generating macroscopically entangled atomic samples.Comment: 4 pages, 3 figure

    To What Extend Does the Technology Disrupstion Affect the Sale of Smes Banana Chips Products in Bandar Lampung?

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    Small and Medium-Sized Enterprises (SMEs) in Indonesia, which is also known as Usaha Mikro Kecil dan Menengah (UMKM), play a significant role in determining national economic performance. Banana chips are the most well-known product in Bandar Lampung. As the provincial capital of Lampung Province, Bandar Lampung becomes the center of trade and services sector which is a vital sector of the downstream industry activity. One of the vital aspect in the downstream of Banana chips industry is selling. This study aims to examine the effect of disruptive technology on the sale of SMEs Banana Chips products in Bandar Lampung. This study conduct the quantitative approach by using multiple regression linear analysis. The findings show that the regression model of selling aspect has 0.594 in R2 value. It means that the regression model is able to represent the real condition about 59,4%. According to the model, among the 6 (six) predictor variables, the most-influencing variable on the sale of Banana chips products is online-based promotion

    Defective phagocytic corpse processing results in neurodegeneration and can be rescued by TORC1 activation

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    This work was supported by NIH Grants R01 GM094452 (K.M.) and F31 GM099425 (J.I.E.), BU Alzheimer's Disease Core Center NIH Grant P30 AG13846, Boston University Undergraduate Research Opportunities Program grants (J.A.T., V.S.), and NIH Grant R01 AG044113 to M.B.F. We thank the Bloomington Stock Center, TRiP at Harvard Medical School, the Kyoto Drosophila Genetic Resource Center, Estee Kurant, Eric Baehrecke, Marc Freeman, and Mary Logan for fly strains. We thank Todd Blute for assistance with electron microscopy and the Developmental Studies Hybridoma Bank for antibodies. (R01 GM094452 - NIH; F31 GM099425 - NIH; R01 AG044113 - NIH; P30 AG13846 - BU Alzheimer's Disease Core Center NIH Grant; Boston University Undergraduate Research Opportunities Program)https://www.jneurosci.org/content/36/11/3170.longPublished versionPublished versio
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