For symmetric classical field theories on principal bundles there are two methods of symmetry reduction: covariant and dynamic. Assume that the classical field theory is given by a symmetric covariant Lagrangian density defined on the first jet bundle of a principal bundle. It is shown that covariant and dynamic reduction lead to equivalent equations of motion. This is achieved by constructing a new Lagrangian defined on an infinite dimensional space which turns out to be gauge group invariant.
Considérons une théorie des champs décrite par une densité lagrangienne définie sur le fibré des jets d’ordre 1 d’un fibré principal. Si la densité est invariante sous l’action du groupe de structure du fibré il y a deux approches possibles pour réduire le système : l’approche covariante et l’approche dynamique. Dans cet article nous montrons que ces deux approches produisent les mêmes équations réduites. Afin d’obtenir ce résultat, nous construisons, à partir de la densité lagrangienne, un nouveau lagrangien défini sur un espace de dimension infinie et invariant sous l’action du groupe des transformations de jauge.
Keywords: Covariant reduction, dynamic reduction, affine Euler-Poincaré equation, covariant Euler-Poincaré equation, Lagrangian, principal bundle field theory
Mot clés : réduction covariante, équations d’Euler-Poincaré affines, équations d’Euler-Poincaré covariantes, Lagrangien, théorie des champs sur un fibré principal
Gay-Balmaz, François 1; Ratiu, Tudor S. 1
@article{AIF_2010__60_3_1125_0, author = {Gay-Balmaz, Fran\c{c}ois and Ratiu, Tudor S.}, title = {A new {Lagrangian} dynamic reduction in field theory}, journal = {Annales de l'Institut Fourier}, pages = {1125--1160}, publisher = {Association des Annales de l{\textquoteright}institut Fourier}, volume = {60}, number = {3}, year = {2010}, doi = {10.5802/aif.2549}, mrnumber = {2680826}, language = {en}, url = {https://aif.centre-mersenne.org/articles/10.5802/aif.2549/} }
TY - JOUR AU - Gay-Balmaz, François AU - Ratiu, Tudor S. TI - A new Lagrangian dynamic reduction in field theory JO - Annales de l'Institut Fourier PY - 2010 SP - 1125 EP - 1160 VL - 60 IS - 3 PB - Association des Annales de l’institut Fourier UR - https://aif.centre-mersenne.org/articles/10.5802/aif.2549/ DO - 10.5802/aif.2549 LA - en ID - AIF_2010__60_3_1125_0 ER -
%0 Journal Article %A Gay-Balmaz, François %A Ratiu, Tudor S. %T A new Lagrangian dynamic reduction in field theory %J Annales de l'Institut Fourier %D 2010 %P 1125-1160 %V 60 %N 3 %I Association des Annales de l’institut Fourier %U https://aif.centre-mersenne.org/articles/10.5802/aif.2549/ %R 10.5802/aif.2549 %G en %F AIF_2010__60_3_1125_0
Gay-Balmaz, François; Ratiu, Tudor S. A new Lagrangian dynamic reduction in field theory. Annales de l'Institut Fourier, Volume 60 (2010) no. 3, pp. 1125-1160. doi : 10.5802/aif.2549. https://aif.centre-mersenne.org/articles/10.5802/aif.2549/
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