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111.
给出相对论系统的Birkhoff函数和Birkhoff函数组、Pfaff作用量、PfaffBirkhoff原理、Birkhoff方程;研究相对论动力学系统的Birkhoff表示方法;根据在无限小变换下相对论Pfaff作用量的不变性和相对论Birkhoff方程的不变性,得到相对论Birkhoff系统的Noether对称性理论和Lie对称性理论;研究相对论Birkhoff系统的代数结构和Poisson积分方法.
关键词:
相对论
Birkhoff系统
Noether对称性
Lie对称性
代数结构
Poisson积分 相似文献
112.
We prove that a sum of free non-covariant duality-symmetric actions does not allow consistent, continuous and local self-interactions that deform the gauge transformations. For instance, non-abelian deformations are not allowed, even in 4 dimensions where Yang–Mills type interactions of 1-forms are allowed in the non-manifestly duality-symmetric formulation. This suggests that non-abelian duality should require to leave the standard formalism of perturbative local field theories. The analyticity of self-interactions for a single duality-symmetric gauge field in four dimensions is also analyzed. 相似文献
113.
114.
Evolution of polarization singularities accompanied by avoided crossing in plasmonic system 下载免费PDF全文
Yi-Xiao Peng 《中国物理 B》2023,32(1):14201-014201
The evolution of polarization singularities supported in a one-dimensional periodic plasmonic system is studied. The lateral inversion symmetry of the system, which breaks the in-plane inversion symmetry and up-down mirror symmetry simultaneously, yields abundant polarization states. A complete evolution process with geometry for the polarization states is traced. In the evolution, circularly polarized points (C points) can stem from 3 different processes. In addition to the previously reported processes occurring in an isolated band, a new type of C point appearing in two bands simultaneously due to the avoided band crossing, is observed. Unlike the dielectric system with a similar structure which only supports at-$\varGamma$ bound states in the continuum (BICs), accidental BICs off the $\varGamma$ point are realized in this plasmonic system. This work provides a new scheme of polarization manipulation for the plasmonic systems. 相似文献
115.
Neutron skin thickness of 90Zr and symmetry energy constrained by charge exchange spin-dipole excitations 下载免费PDF全文
The charge exchange spin-dipole (SD) excitations of \begin{document}$ ^{90} $\end{document} ![]()
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Zr are studied using the Skyrme Hartee-Fock plus proton-neutron random phase approximation with SAMi-J interactions. The experimental value of the model-independent sum rule obtained from the SD strength distributions of \begin{document}$ ^{90} $\end{document} ![]()
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Zr(p, n)\begin{document}$ ^{90} $\end{document} ![]()
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Nb and \begin{document}$ ^{90} $\end{document} ![]()
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Zr(n, p)\begin{document}$ ^{90} $\end{document} ![]()
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Y is used to deduce the neutron skin thickness. The neutron skin thickness \begin{document}$ \Delta r_{np} $\end{document} ![]()
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of \begin{document}$ ^{90} $\end{document} ![]()
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Zr is extracted as \begin{document}$ 0.083\pm0.032 $\end{document} ![]()
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fm, which is similar to the results of other studies. Based on the correlation analysis of the neutron skin thickness \begin{document}$ \Delta r_{np} $\end{document} ![]()
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and the nuclear symmetry energy J as well as its slope parameter L, a constraint from the extracted \begin{document}$ \Delta r_{np} $\end{document} ![]()
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leads to the limitation of J to \begin{document}$ 29.2 \pm 2.6 $\end{document} ![]()
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MeV and L to \begin{document}$ 53.3 \pm 28.2 $\end{document} ![]()
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MeV. 相似文献
116.
The deformed mean field of nuclei exhibits various geometrical and dynamical symmetries which manifest themselves as various
types of rotational and decay patterns. Most of the symmetry operations considered so far have been defined for a situation
wherein the angular momentum coincides with one of the principal axes and the principal axis cranking may be invoked. New
possibilities arise with the observation of rotational features in weakly deformed nuclei and now interpreted as magnetic
rotational bands. More than 120 MR bands have now been identified by filtering the existing data. We present a brief overview
of these bands. The total angular momentum vector in such bands is tilted away from the principal axes. Such a situation gives
rise to several new possibilities including breaking of chiral symmetry as discussed recently by Frauendorf. We present the
outcome of such symmetries and their possible experimental verification. Some possible examples of chiral bands are presented. 相似文献
117.
The form invariance of Appell equations of holonomic mechanical systems under the infinitesimal transformations of groups is studied. The definition and the criterion of the form invariance of Appell equations are given. This form invariance can lead to a conserved quantity under certain conditions. 相似文献
118.
The dynamical symmetries and adjoint symmetries of nonlinear nonholonomic constrained mechanical systems are analysed in two kinds of geometrical frameworks whose evolution equations are Routh's equations and generalized Chaplygin's equations, respectively. The Lagrangian inverse problem and the interrelation between Noether's symmetries and dynamical symmetries are briefly concerned with. Finally an illustrative example is analysed. 相似文献
119.
本文给出了具有两个抛线解的中心对称三次系统存在在极限环的条件,它可能也是充要条件。 相似文献
120.
D.R. Jensen 《Journal of multivariate analysis》1997,60(2):188-202
Distribution-free results beyond Gauss-Markov theory are found under weak assumptions regarding the errors. Symmetry, unimodality, and location-scale families are studied in estimation; nonstandard versions of Gauss–Markov results are given; and distribution-free confidence sets are tightened under symmetry and unimodality of errors. Normal-theory approximate tests are seen to exhibit monotone power in certain classes of symmetric unimodal errors. 相似文献