首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
In this paper we show the scattering problem's equation of principal chiral model with Wess-Zumino-Witten term.Two sets of symmetry transforms are given and four series of conserved currents are obtained, in which two of them are Noether types and the others are not. Finally the Kac-Moody algebra is discussed.  相似文献   

2.
In this paper we first present the gauge invariant conserved Noether current for the Yang-Mi11s theory, which is nonlocal is some sense. Then we introduce for the two dimensional chiral model, plain and supersymmetric, the nonlocal one-complex parameter-dependent symmetric generators, which shift the Lagrangian density by a total divergence. Both the equations of motion and the energy momentum density are tnvaunt. The associated ically Into infinite Noether current may be expanded analyt-series of nonlocal currents.  相似文献   

3.
In this paper,we obtain the expressions of electromagnetic current,charged current,baryon current and neutral weak current in the Skyrme model by means of the gauge transformations.A relation available for both cases of mπ=0 and mπ≠0 is given.The mean square radius < r2 >A of axial form factor is calculated and the result shpws that its value is much smaller than the experimental datum.In addition,the expressions of < r2 > M,T=l and < r2 >M,T=0 in our derivations are different from those given in Ref.[4] by a factor 3/5.  相似文献   

4.
We present a general approach to get the anomalous weak charged current of leptons and quarks in a substructure mode1,in which quarks, leptons and W-bosons are composed of preons (fermions and scalar bosons). We have shown that the (V+A) current can be determined by the structure of leptons and quarks and the anomalous weak current can be very small. In particular, it can approach zero, if the wave function of leptons (or quarks) has aspinor structure (I-P/mf)F.  相似文献   

5.
金属氢化物放氢过程数值分析   总被引:1,自引:0,他引:1  
通过分析外壁处有恒温热源条件下贮氢合金放氢过程的传热现象,建立多孔介质的传热模型,研究分析了真空烧结的多孔贮氢复合材料放氢过程中温度场和速度场变化规律.计算结果表明,当反应焓变小于外界传入的热量时,温度逐渐上升.由于从内壁到外壁热阻很大,导致靠近内壁处温度难以上升,氢气也就难以释放,故为提高合金利用率,须减小传热间隔,并适当提高初始温度。氢气流速刚开始时大,很快趋于平稳.孔隙率对温度分布和流速影响很大,孔隙率越大,则气流速度更平缓易于控制,但使合金含氢量减小.选取合适的贮氢合金孔隙率对金属氢化物放氢过程较为关键.  相似文献   

6.
Due to the possible production of neutral and charge heavy leptons by vμ, models consisting of four elements per "line", e.g. ve, e-, E0, E- vμ, μ-, M0, M- vτ, τ-, T0, T- ……are analysed. Non-diagonal neutral currents cannot be avoided. Nevertheless, a model is proposed within SU(2)×U(1) in which the process μ can still be suppressed by the Bjorken-Lane-Weinberg mechanism; various production cross-sections for heavy leptons are reasonable when compared with experiments. Models corresponding to SU(3)×U(1) and still higher symmetries are discussed.  相似文献   

7.
邓文基 《物理学报》2001,50(8):1425-1428
实空间中的概率流概念和概率守恒定理被推广到希尔伯特(Hilbert)状态空间,从而得到了概率流算符的通式.应用一般形式的概率流算符公式,还导出了紧束缚模型中单电子和互作用多电子系统的概率流算符,并以异常简单的方式证明了反射-透射流归一化条件 关键词: 希尔伯特空间 概率流算符 紧束缚模型  相似文献   

8.
"Electric" chaise currents with gauge-dependent isotopic axis are gauge invariant Noether currents. These currnnts include themselves the contribution of gauge field. "Magrnetic" poles are related to the topologically nontrivial orientation of isotopic axis. The dual symmetry trans-forms a known conserved current into infinitely many ved currents. The induced Noether charges of vacuum different chiral boundary condition and the topological background charges always compensate each other.  相似文献   

9.
The 3×3 super extended eigenvalue problem is considered. We deduce a class of completely integrable equations. Its reduced forms are givan and their infinite conserved currents have been discussed.  相似文献   

10.
本文计算了近地面湍流边界层的速度分布。根据跃移运动的临界摩擦速度及湍流边界层的计算,给出了产生跃移运动的边界层范围,假定运动沙粒与静止沙粒的接触点上没有相互滑移运动,提出了旋转力矩是在跃移运动初始阶段由升力和粒子间相互作用力产生的,并计算了该力矩作用时间和大小。计算了跃移轨迹,得到了跃移的诸运动要素。与实验结果比较,在所考虑范围内,其结果是一致的。  相似文献   

11.
相对论性Birkhoff系统的Lie对称性和守恒量   总被引:13,自引:0,他引:13       下载免费PDF全文
傅景礼  王新民 《物理学报》2000,49(6):1023-1027
给出相对论性Birkhoff系统的Pfaff-Birkhoff原理和Birkhoff方程.由微分方程在无限小变换下的不变性,定义相对论性Birkhoff系统无限小变换生成元,建立Lie对称的确定方程,得到结构方程和守恒量.并研究该系统的Lie对称性逆问题.给出实例以说明结果的应用. 关键词:  相似文献   

12.
利用三轴粒子-转子模型计算了(193)Tl超形变带γ跃迁能量,运动学转动惯量J(1)和动力学转动惯量J(2),并与实验值进行比较得到了满意的结果;预言了B(M1)值以及动力学电四极矩Q(1)和Q(2)指出在超形变带的分析中粒子-转子模型是一种可以采用的方法.  相似文献   

13.
一阶Lagrange系统的Lie对称性与守恒量   总被引:9,自引:0,他引:9       下载免费PDF全文
梅凤翔  尚玫 《物理学报》2000,49(10):1901-1903
将一阶微分方程组化成一阶Lagrange方程.利用常微分方程在无限小变换下的不变性,建立L ie对称性的确定方程.给出Lie对称性导致守恒量的条件以及守恒量的形式. 关键词: 一阶Lagrange系统 Lie对称性 守恒量  相似文献   

14.
张毅  尚玫  梅凤翔 《中国物理》2000,9(6):401-407
In this paper, the symmetries and the conserved quantities for systems of generalized classical mechanics are studied. First, the generalized Noether's theorem and the generalized Noether's inverse theorem of the systems are given, which are based upon the invariant properties of the canonical action with respect to the action of the infinitesimal transformation of r-parameter finite group of transformation; second, the Lie symmetries and conserved quantities of the systems are studied in accordance with the Lie's theory of the invariance of differential equations under the transformation of infinitesimal groups; and finally, the inner connection between the two kinds of symmetries of systems is discussed.  相似文献   

15.
分析了稳态强磁场实验装置(Steady High Magnetic Field Facilities,SHMFF)水蓄冷系统的特征,并介绍了安装于蓄冷罐用于验证自然分层法应用于该系统可行性的布水装置.利用冷水机组冷冻水进、出水温度变化对蓄冷过程中的斜温层厚度进行了概算,从而初步验证该布水器的性能.研究结果将为稳态强磁场实验装置水蓄冷系统是否采用自然分层法提高蓄冷量提供参考依据.  相似文献   

16.
Considering that the IBM and IBFM cranking calculations in the lowest order of angular frequency can give reasonably good estimates for the moment of inertia,we extend them to study the dependence of the moment of inertia on the higher order terms.We find that the analytic expressions for the correction terms can be derived.Numerical calculations for 154Gd and 161Er are performed and compared with experiment.The Hamiltonian is taken from a microscopic approach.Calculated results show that the properties of higher order terms depend on the deformation of rotating system but the correction yields only limited effect when ω is small.  相似文献   

17.
王德和 《物理学报》1992,41(5):792-797
本文讨论存在于晶态和非晶态硅(锗)中的原子相关性及二者之间的联系,给出原子相关性的定量表达式。在此基础上建造一个包含400个原子的非晶硅(锗)的结构模型,其主要参数均与实验符合得很好。 关键词:  相似文献   

18.
包含伺服约束的非完整系统的Lie对称性与守恒量   总被引:10,自引:0,他引:10       下载免费PDF全文
梅凤翔 《物理学报》2000,49(7):1207-1210
利用代数方程和微分方程在无限小变换下的不变性,研究带有伺服约束的非完整系统的Lie 对称性.给出Lie对称性的确定方程、限制方程、结构方程,并给出守恒量的形式. 关键词: 非完整系统 伺服约束 Lie对称性 守恒量  相似文献   

19.
Using a complex representation of planar motions, we show that the dynamical conserved quantities associated to the isotropic harmonic oscillator (Fradkin–Jauch–Hill tensor) and to the Kepler's problem (Laplace–Runge–Lenz vector) find a very simple and natural interpretation. In this frame we also establish in an elementary way the relation which connects them.  相似文献   

20.
在Skyrme模型中关于解析质量计算的研究   总被引:1,自引:0,他引:1  
张寿  林进虎 《计算物理》1992,9(2):219-222
本文用Reduce语言[1]研究了Skyrme模型[2、3、4]中孤立子质量的计算方法。上机计算结果表明,矩阵方法和具体展开方法比一般算符表达式更为优越。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号