125,116 research outputs found

    Multiple Chirality in Nuclear Rotation: A Microscopic View

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    Covariant density functional theory and three-dimensional tilted axis cranking are used to investigate multiple chirality in nuclear rotation for the first time in a fully self-consistent and microscopic way. Two distinct sets of chiral solutions with negative and positive parities, respectively, are found in the nucleus 106Rh. The negative-parity solutions reproduce well the corresponding experimental spectrum as well as the B(M1)/B(E2) ratios of the transition strengths. This indicates that a predicted positive-parity chiral band should also exist. Therefore, it provides a further strong hint that multiple chirality is realized in nuclei.Comment: 15 pages, 5 figures, 1 tabl

    Detecting relic gravitational waves in the CMB: A statistical bias

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    Analyzing the imprint of relic gravitational waves (RGWs) on the cosmic microwave background (CMB) power spectra provides a way to determine the signal of RGWs. In this Letter, we discuss a statistical bias, which could exist in the data analysis and has the tendency to overlook the RGWs. We also explain why this bias exists, and how to avoid it.Comment: 4 pages, 1 figur

    Variational-Iterative Solution of Ground State for Central Potential

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    The newly developed iterative method based on Green function defined by quadratures along a single trajectory is combined with the variational method to solve the ground state quantum wave function for central potentials. As an example, the method is applied to discuss the ground state solution of Yukawa potential, using Hulthen solution as the trial function.Comment: 9 pages with 1 tabl

    A Generalization of Mathieu Subspaces to Modules of Associative Algebras

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    We first propose a generalization of the notion of Mathieu subspaces of associative algebras A\mathcal A, which was introduced recently in [Z4] and [Z6], to A\mathcal A-modules M\mathcal M. The newly introduced notion in a certain sense also generalizes the notion of submodules. Related with this new notion, we also introduce the sets σ(N)\sigma(N) and τ(N)\tau(N) of stable elements and quasi-stable elements, respectively, for all RR-subspaces NN of A\mathcal A-modules M\mathcal M, where RR is the base ring of A\mathcal A. We then prove some general properties of the sets σ(N)\sigma(N) and τ(N)\tau(N). Furthermore, examples from certain modules of the quasi-stable algebras [Z6], matrix algebras over fields and polynomial algebras are also studied.Comment: A new case has been added; some mistakes and misprints have been corrected. Latex, 31 page

    The mass estimate in narrow-line Seyfert 1 galaxies

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    It is possible that narrow-line Seyfert 1 galaxies (NLS1s) are in the early stage of active galactic nuclei (AGNs) evolution. It is important to estimate the mass of supermassive black hole (SBH) in NLS1s. Here we considered the different kinds of methods to estimate the SBH masses in NLS1s. The virial mass from the Hβ\beta linewidth assuming random orbits of broad line regions (BLRs) is consistent with that from the statured soft X-ray luminosity, which showed that most of NLS1s are in the super-Eddington accretion state. The mass from the [O III] linewidth is systematically larger than that from above two methods. It is necessary to measure he bulge stellar dispersion and/or bulge luminosity in NLS1s.Comment: 2 Pages, 1 figure, in Prof. IAU Symposium No. 222, "The interplay among Black Holes, Stars and ISM in Galactic Nuclei ", eds. T. Storchi-Bergmann, Luis Ho and H. R. Schmit

    An optimal factor analysis approach to improve the wavelet-based image resolution enhancement techniques

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    The existing wavelet-based image resolution enhancement techniques have many assumptions, such as limitation of the way to generate low-resolution images and the selection of wavelet functions, which limits their applications in different fields. This paper initially identifies the factors that effectively affect the performance of these techniques and quantitatively evaluates the impact of the existing assumptions. An approach called Optimal Factor Analysis employing the genetic algorithm is then introduced to increase the applicability and fidelity of the existing methods. Moreover, a new Figure of Merit is proposed to assist the selection of parameters and better measure the overall performance. The experimental results show that the proposed approach improves the performance of the selected image resolution enhancement methods and has potential to be extended to other methods

    Matching the Quasi Parton Distribution in a Momentum Subtraction Scheme

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    The quasi parton distribution is a spatial correlation of quarks or gluons along the zz direction in a moving nucleon which enables direct lattice calculations of parton distribution functions. It can be defined with a nonperturbative renormalization in a regularization independent momentum subtraction scheme (RI/MOM), which can then be perturbatively related to the collinear parton distribution in the MS\overline{\text{MS}} scheme. Here we carry out a direct matching from the RI/MOM scheme for the quasi-PDF to the MS\overline{\text{MS}} PDF, determining the non-singlet quark matching coefficient at next-to-leading order in perturbation theory. We find that the RI/MOM matching coefficient is insensitive to the ultraviolet region of convolution integral, exhibits improved perturbative convergence when converting between the quasi-PDF and PDF, and is consistent with a quasi-PDF that vanishes in the unphysical region as the proton momentum PzP^z\to \infty, unlike other schemes. This direct approach therefore has the potential to improve the accuracy for converting quasi-distribution lattice calculations to collinear distributions.Comment: 18 pages, 6 figure
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