138,072 research outputs found

    Microstructural evolution in materials during thermal processing

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    Copyright © 2012 Joseph K. L. Lai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This article has been made available through the Brunel Open Access Publishing Fund.This article is made available through the Brunel Open Access Publishing Fund

    Diagnostics of macroscopic quantum states of Bose-Einstein condensate in double-well potential by nonstationary Josephson effect

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    We propose a method of diagnostic of a degenerate ground state of Bose condensate in a double well potential. The method is based on the study of the one-particle coherent tunneling under switching the time-dependent weak Josephson coupling between the wells. We obtain a simple expression that allows to determine the phase of the condensate and the total number of the particles in the condensate from the relative number of the particles in two wells Δn=n1n2\Delta n =n_1-n_2 measured before the Josephson coupling is switched on and after it is switched off. The specifics of the application of the method in the cases of the external and the internal Josephson effect are discussed.Comment: 3 page

    Repeating head-on collisions in an optical trap and the evaluation of spin-dependent interactions among neutral particles

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    A dynamic process of repeating collisions of a pair of trapped neutral particles with weak spin-dependent interaction is designed and studied. Related theoretical derivation and numerical calculation have been performed to study the inherent coordinate-spin and momentum-spin correlation. Due to the repeating collisions the effect of the weak interaction can be accumulated and enlarged, and therefore can be eventually detected. Numerical results suggest that the Cr-Cr interaction, which has not yet been completely clear, could be thereby determined. The design can be in general used to determine various interactions among neutral atoms and molecules, in particular for the determination of very weak forces.Comment: 15 pages, 7 figure

    Low-lying states in even Gd isotopes studied with five-dimensional collective Hamiltonian based on covariant density functional theory

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    Five-dimensional collective Hamiltonian based on the covariant density functional theory has been applied to study the the low-lying states of even-even 148162^{148-162}Gd isotopes. The shape evolution from 148^{148}Gd to 162^{162}Gd is presented. The experimental energy spectra and intraband B(E2)B(E2) transition probabilities for the 148162^{148-162}Gd isotopes are reproduced by the present calculations. The relative B(E2)B(E2) ratios in present calculations are also compared with the available interacting boson model results and experimental data. It is found that the occupations of neutron 1i13/21i_{13/2} orbital result in the well-deformed prolate shape, and are essential for Gd isotopes.Comment: 11pages, 10figure
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