scholarly journals Noether’s theorem and the Willmore functional

2016 ◽  
Vol 9 (3) ◽  
pp. 217-234 ◽  
Author(s):  
Yann Bernard

AbstractNoether’s theorem and the invariances of the Willmore functional are used to derive conservation laws that are satisfied by the critical points of the Willmore energy subject to generic constraints. We recover in particular previous results independently obtained by R. Capovilla and J. Guven, and by T. Rivière. Several examples are considered in detail.

Author(s):  
Laurent Baulieu ◽  
John Iliopoulos ◽  
Roland Sénéor

General introduction with a review of the principles of Hamiltonian and Lagrangian mechanics. The connection between symmetries and conservation laws, with a presentation of Noether’s theorem, is included.


Author(s):  
Daniela Manolea

The study is explanatory-interpretative and argues the practical character of Physics. It starts from premise that formation of a correct conception of the world begins with the understanding of physics. It is one of the earliest chapters of human knowledge, studying the material world from the microscopic level of the particles to the macroscopic level of the celestial body. As an example for the practical importance of applying the laws of physics take the set of physical laws of conservation, in particular, it explains the practical impact of Emmy Noether's Theorem.


Author(s):  
Shaofan Li ◽  
Anurag Gupta ◽  
Xanthippi Markenscoff

In this paper, we present new conservation laws of linear elasticity which have been discovered. These newly discovered conservation laws are expressed solely in terms of the Cauchy stress tensor, and they are genuine, non–trivial conservation laws that are intrinsically different from the displacement conservation laws previously known. They represent the variational symmetry conditions of combined Beltrami–Michell compatibility equations and the equilibrium equations. To derive these conservation laws, Noether's theorem is extended to partial differential equations of a tensorial field with general boundary conditions. By applying the tensorial version of Noether's theorem to Pobedrja's stress formulation of three–dimensional elasticity, a class of new conservation laws in terms of stresses has been obtained.


1993 ◽  
Vol 60 (4) ◽  
pp. 954-958 ◽  
Author(s):  
L. Cveticanin

In this paper, a method for obtaining conservation laws of dynamic systems with variable mass is developed. It is based on Noether’s theorem to the existence of conservation laws and D’Alembert’s variational principle. In the general case, a dynamic system with variable mass is purely nonconservative. Noether’s identity for such a case is expanded by the terms that describe the mass variation. If Noether’s identity if satisfied, a conservation law exists. Two groups of systems with variable mass are considered: a nonlinear vibrating machine and a rotor with variable mass. For these systems, conservation laws are obtained using the procedure developed in this paper.


2012 ◽  
Vol 24 (10) ◽  
pp. 1250030 ◽  
Author(s):  
LUCÍA BUA ◽  
IOAN BUCATARU ◽  
MODESTO SALGADO

In this paper, we study symmetries, Newtonoid vector fields, conservation laws, Noether's theorem and its converse, in the framework of the k-symplectic formalism, using the Frölicher–Nijenhuis formalism on the space of k1-velocities of the configuration manifold.For the case k = 1, it is well known that Cartan symmetries induce and are induced by constants of motions, and these results are known as Noether's theorem and its converse. For the case k > 1, we provide a new proof for Noether's theorem, which shows that, in the k-symplectic formalism, each Cartan symmetry induces a conservation law. We prove that, under some assumptions, the converse of Noether's theorem is also true and we provide examples when this is not the case. We also study the relations between dynamical symmetries, Newtonoid vector fields, Cartan symmetries and conservation laws, showing when one of them will imply the others. We use several examples of partial differential equations to illustrate when these concepts are related and when they are not.


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