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1.
Based on the canonical action,a generalized canonical first Noether theorem and Poicare-Cartan integralinvariant for a system with a singular high-order Lagrangian are derived.It is worth while to point out that the constraints are invariant under the total variation of canonical variables including time.We can also deduce the result,which differs from the previous work to reuire that the constraints are invariant under the simultaneous variations of canonical variables.A counter example to a conjecture of the Dirac for a system with a singular high-order Lagrangian is given,in which there is no linearization of constraint.  相似文献   

2.
张毅 《中国物理 B》2011,20(3):34502-034502
This paper focuses on a new symmetry of Hamiltonian and its conserved quantity for a system of generalized classical mechanics.The differential equations of motion of the system are established.The definition and the criterion of the symmetry of Hamiltonian of the system are given.A conserved quantity directly derived from the symmetry of Hamiltonian of the generalized classical mechanical system is given.Since a Hamilton system is a special case of the generalized classical mechanics,the results above are equally applicable to the Hamilton system.The results of the paper are the generalization of a theorem known for the existing nonsingular equivalent Lagrangian.Finally,two examples are given to illustrate the application of the results.  相似文献   

3.
ZHANG Yi 《理论物理通讯》2008,50(10):851-854
For a Birkhoffing system in the event space, a general approach to the construction of conservation laws is presented. The conservation laws are constructed by finding corresponding integrating factors for the parametric equations of the system. First, the parametric equations of the Birkhoffian system in the event space are established, and the definition of integrating factors for the system is given; second the necessary conditions for the existence of conservation laws are studied in detail, and the relation between the conservation laws and the integrating factors of the system is obtained and the generalized Killing equations for the determination of the integrating factors are given; finally, the conservation theorem and its inverse for the system are established, and an example is given to illustrate the application of the results.  相似文献   

4.
Lie symmetries and invariants of constrained Hamiltonian systems   总被引:1,自引:0,他引:1       下载免费PDF全文
刘荣万  陈立群 《中国物理》2004,13(10):1615-1619
According to the theory of the invariance of ordinary differential equations under the infinitesimal transformations of group, the relations between Lie symmetries and invariants of the mechanical system with a singular Lagrangian are investigated in phase space. New dynamical equations of the system are given in canonical form and the determining equations of Lie symmetry transformations are derived. The proposition about the Lie symmetries and invariants are presented. An example is given to illustrate the application of the result in this paper.  相似文献   

5.
In this paper we show that the first integrals of the discrete equation of motion for nonconservative and nonholonomic mechanical systems can be determined explicitly by investigating the invariance properties of the discrete Lagrangian. The result obtained is a discrete analogue of the generalized theorem of Noether in the Calculus of variations.  相似文献   

6.
马善钧  黄沛天  颜蓉  赵红霞 《中国物理》2006,15(10):2193-2196
Based on the three-order Lagrangian equations, Hamilton's function of acceleration H^* and generalized acceleration momentum P^*α are defined, and pseudo-Hamilton canonical equations corresponding to three-order Lagrangian equations are obtained. The equations are similar to Hamilton's canonical equations of analytical mechanics in form.  相似文献   

7.
The nonlocal symmetry of the generalized fifth order KdV equation(FOKdV) is first obtained by using the related Lax pair and then localizing it in a new enlarged system by introducing some new variables. On this basis, new Ba¨cklund transformation is obtained through Lie's first theorem. Furthermore, the general form of Lie point symmetry for the enlarged FOKdV system is found and new interaction solutions for the generalized FOKdV equation are explored by using a symmetry reduction method.  相似文献   

8.
罗绍凯 《中国物理快报》2007,24(9):2463-2466
For a Lagrangian system with the action of small disturbance, the Lie symmetrical perturbation and a new type of non-Noether adiabatic invariant are presented in general infinitesimal transformation groups. On the basis of the invariance of disturbed Lagrangian systems under general infinitesimal transformations, the determining equations of Lie symmetries of the system are constructed. Based on the definition of higher-order adiabatic invariants of a mechanical system, a new type of adiabatic invariant, i.e. generalized Lutzky adiabatic invariants, of a disturbed Lagrangian system are obtained by investigating the perturbation of Lie symmetries t'or a Lagrangian system with the action of small disturbance. Finally, an example is given to illustrate the application of the method and results.  相似文献   

9.
乔永芬  张耀良  韩广才 《中国物理》2002,11(10):988-992
In this paper,we present a general approach to the construction of conservation laws for generalized classical dynamical systems.Firstly,we give the definition of integrating factors and ,secondly,we study in detail the necessary conditions for the existence of conserved quantities.Then we establish the conservation theorem and its inverse for the hamilton‘s canonical equations of motion of holonomic nonconservative dynamical systems in generalized classical mechanics.Finally,we give an example to illustrate the application of the results.  相似文献   

10.
李彦敏  梅凤翔 《中国物理 B》2010,19(8):80302-080302
<正>Stability for the manifolds of equilibrium states of a generalized Birkhoff system is studied.A theorem for the stability of the manifolds of equilibrium states of the general autonomous system is used to the generalized Birkhoffian system and two propositions on the stability of the manifolds of equilibrium states of the system are obtained.An example is given to illustrate the application of the results.  相似文献   

11.
李爱民  张晓沛  李子平 《物理学报》2003,52(5):1057-1060
由扩展正则作用量导出了高阶微商奇异Lagrange量系统的扩展正则Noether恒等式.从广义约束Hamilton系统相空间中对称性分析,给出高阶微商系统Dirac猜想的一个反例. 用正则Noether定理、 正则Noether恒等式和扩展正则Noether恒等式说明在此反例中Dirac猜想失效, 讨论中没有将约束线性化. 关键词: 高阶微商系统 约束Hamilton系统 正则对称性 Dirac猜想  相似文献   

12.
A generalization of Noether's first theorem in phase space for an invariant system with a singular Lagrangian in field theories is derived and a generalization of Noether's second theorem in phase space for a noninvariant system in field theories is deduced. A counterexample is given to show that Dirac's conjecture fails. Some preliminary applications of the generalized Noether second theorem to the gauge field theories are discussed. It is pointed out that for certain systems with a noninvariant Lagrangian in canonical variables for field theories there is also a Dirac constraint. Along the trajectory of motion for a gauge-invariant system some supplementary relations of canonical variables and Lagrange multipliers connected with secondary first-class constraints are obtained.  相似文献   

13.
约束系统正则形式的对称性质   总被引:4,自引:0,他引:4       下载免费PDF全文
李子平 《物理学报》1992,41(5):710-719
本文导出场论中用奇异拉氏量描述的系统正则形式的广义Noether第一定理(GNFT),导出无限连续群下变更性系统正则形式的广义Noether恒等式(GNI),讨论了它们在Dirac约束理论中的应用。给出一个新的反倒,说明Dirac猜想失效,指出某些变更性系统也具有Dirac约束,讨论了GNI在色动力学中的应用。 关键词:  相似文献   

14.
李子平 《中国物理 C》1995,19(11):1012-1018
分别从正规和奇异拉氏量系统的相空间生成泛函出发,导出了增广相空间中整体对称下的正则形式Ward恒等式.考虑对应的定域交换,得到了量子水平的守恒荷,给出了正则形式的量子Noether定理.讨论了在核子和π介子相互作用中的初步应用.  相似文献   

15.
Starting from the phase-space generating functional of the Green function for a system with singular higher order Lagrangian, the generalized canonical Ward identities under the global symmetry transformation in phase space is deduced. The local transformation connected with this global symmetry transformation is studied, and the quantal conservation laws are obtained for such a system. We give a preliminary application to higher derivative Yang-Mills theory; a generalized quantal BRS conserved quantity is found.  相似文献   

16.
The quantization for a system containing subsidiary constraints (in configuration space) with a singular Lagrangian is studied, in certain case which can be brought into the theoretical framework of constrained Hamiltonian system. A modified Dirac-Bergmann algorithm for the calculation of all phase-space constraints in those systems is derived. The path integral quantization is formulated by using the Faddeev-Senjanovic scheme. The classical and quantum canonical symmetries (Noether theorem in canonical formalism) are established for such a system. An example is given to illustrate that the connection between the symmetry and conservation law in classical theory are not always validity in the quantum theory.  相似文献   

17.
李子平 《中国物理 C》1995,19(5):405-412
导出了高阶微商奇异拉氏量系统正则形式的Ward恒等式并将其应用于广义色动力学(QCD),得到了广义QCD中规范场和鬼场正规顶角间的某些新关系,它们有别于BRS不变性所导致的结果;还得到了广义QCD中的PCAC和AVV顶角的Ward恒等式.  相似文献   

18.
Based on the phase-space generating functional of the Green function for a system with a regular/singular higher-order Lagrangian, the quantal Poincaré-Cartan integral invariant (QPCII) for the higher-order Lagrangian in field theories is derived. It is shown that this QPCII is equivalent to the quantal canonical equations. For the case in which the Jacobian of the transformation may not be equal to unity, the QPCII can still be derived. This case is different from the quantal first Noether theorem. The relations between QPCII and a canonical transformation and those between QPCII and the Hamilton-Jacobi equation at the quantum level are also discussed.Received: 26 May 2004, Revised: 2 December 2004, Published online: 16 March 2005  相似文献   

19.
李子平 《物理学报》1996,45(10):1601-1608
从奇异拉氏量系统相空间路径积分的量子化形式出发,导出了系统在增广相空间整体变换下的广义正则Ward恒等式和量子水平的守恒荷,一般这些守恒荷有别于经典Noether荷.给出了在杨-Mils场论中的应用,找到了新守恒荷  相似文献   

20.
On the basis of the phase-space generating function of Green function for a system with a regular/singular Lagrangian, the quantal Poincaré-Cartan integral invariant (PCII) for field theory is derived. This PCII is equivalent to the quantal canonical equations. For this case in which the Jacobian of the transformation does not equalto unity, the quantal PCII can still be derived. This case is different from the quantal first Noether theorem. The quantal PCII connected with canonical equations and canonical transformation is also discussed.  相似文献   

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