Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2018-06-02
Abstract： " Using the idea of decomposability of gauge potential and internal structure put forward by Duan Yi Shi, we decompose gauge potential of SO(n) group in the unit vector field by using geometric algebra method, We get the general decomposition form and discuss the properties of this decomposition. In this paper, we give the form of decomposition of SU(2) group and U(1) group with unit vector field, which is exactly the result given by famous physicist Fadeev in 1999. The local topological structure of Gauss-Bonnet-Chern density is discussed by using the general form of decomposition of SO(n) gauge potential.The global topological structure of the density is Gauss-Bonnet-Chern theorem, and the Morse theoretical form of Euler- Poincar é characteristic is easily obtained from the topological structure. A new circulation condition is obtained by using the normal potential decomposition of SU( 2) gauge potential to study -1 / 2 Bose-Einstein condensate, which is also a generalization of the Mernin-Ho relation. Finally, using the relation between Torsion tensor and U(1) gauge theory of three-dimensional Riemannian geometry discovered by Duan Yi-shi, the relation between dislocation line and link number is studied by using U(1) gauge potential decomposition.
Peer Review Status:
Awaiting Review
Subjects: Astronomy >> Galaxy and Cosmology submitted time 2018-04-25
Abstract： The present paper is a continuation and extension of [1] to CLASH clusters. We study the total, the dark matter density profiles, and correlations in a subgroup of CLASH clusters, as we did for the Newman’s clusters. As in the case of Newman clusters, we find that the DM density profile is strongly influenced by interactions with baryons, and the energy and angular momentum transferred from baryons to DM through dynamical friction. The inner slope of the dark matter density profiles of the clusters are usually flatter than the Navarro-Frenk-White profile inner slope, with maximum value -0.79, and minimum -0.30. As in the case of Newman clusters, there are a series of correlations among the slope α of the dark matter profile, and: a. the core radius of clusters; b. the effective radius R e ; c. the mass of the Brightest Central Galaxy (BCG); d. the total baryonic mass, and stellar mass of the clusters. We also found a correlation between the effective radius and the virial mass. The clusters structure, their total and DM density profiles, and the correlations are understood in a double phase scenario. In the first dissipative phase, the BGC forms. In the second dissipationless phase, the interactions between of baryon cluamps with DM through dynamical friction (DF), flattens the DM distribution. The final result of the two phases is the formation of clusters with different DM distribution, inner slopes, and several correlations between characteristic quantities of the clusters
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Galaxy and Cosmology submitted time 2018-03-27
Abstract： In this paper, we show how baryonic physics can solve the problem of the striking diversity in dwarf galaxies rotation curves shapes. To this aim, we compare the distribution of galaxies of the SPARC sample, in the plane V 2kpc -V last (being V 2kpc the galaxy rotation velocity at 2 kpc, and V last that outermost one) with that of galaxies that we simulated taking account of baryonic effects. The scatter in the rotation curves in the V 2kpc -V lastplane, and the trend of the SPARC sample’s, and our simulated galaxies’, distribution is in good agreement. The solution of the ”diversity” problem lies in the ability of baryonic process to produce non self-similar haloes, contrary to DM-only simulations. We show also that baryonic effects can reproduce the rotation curves of galaxies like IC2574 characterized by a slow rising with radius. A solution to the diversity problem can be obtained taking appropriately into account the baryon physics effects.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Galaxy and Cosmology submitted time 2018-03-27
Abstract： We study how deviations from spherical symmetry of a system, produced by angular momentum, and shear stress, modify the spherical collapse model, as linear density threshold for collapse of the non-relativistic com-ponent (δ c ) and its virial overdensity (∆ V ), in Einstein-de Sitter and ΛCDM models. We modify the sphericalcollapse model to take account of the shear term and angular momentum term. We find that the non-sphericalterms change the non-linear evolution of the system and that the collapse stops “naturally” at the virial ra-dius. Moreover, values of the linear overdensity parameter and of ∆ V are modified with respect to the standard spherical collapse model.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2017-12-01
Abstract： In order to commemorate Professor Duan Yi-Shi, I hereby publish in Helv. Phys. Acta,(68(1995)513.） article on the Internet。 By means of methods of the geometric algebra the general decomposition of the spin connections on the sphere bundle of a compact $n$-dimensional Riemannian manifold has been studied in detail. Using this decomposition theory it is shown that the Gauss-Bonnet-Chern density of the Euler- Poincar$\acute{e}$ characteristic can be expressed in terms of a smooth vector field $\vec{\phi}$ and taken the form of the $\delta$ function $\delta(\vec{\phi})$.The topological structure of the Gauss-Bonnet-Chern density is detailed. Furthermore the Morse theory formula of the Euler-Poincar$\acute{e}$ characteristic has been obtained via the topological structure.
Peer Review Status:Awaiting Review
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