Canonical
Noether
symmetries
and
commutativity
properties
for
gauge
systems
∗
Abstract
ForadynamicalsystemdefinedbyasingularLagrangian,canonicalNoethersymmetriesarecharacterizedintermsoftheircommutationrelationswiththeevolutionoperatorsofLagrangianandHamiltonianformalisms.Separatecharacterizationsaregiveninphasespace,invelocityspace,andthroughanevolutionoperatorthatlinksbothspaces.
Introduction
Mostphysicaltheoriesimplementthedynamicsasaresultoftheapplicationofavariationalprinciple,thatis,bymeansofaLagrangian.Amongthedynamicalsymmetriesofthesetheories,thatis,transformationsthatmapsolutionsoftheequationsofmotionintosolutions,wecansingleouttheNoethersymmetries,thatis,thecontinuoustransformationsthatleavetheactioninvariant—exceptforboundaryterms.Inaddition,ifweaimtomovethedescriptionofthedy-namicsfromthetangentbundle(velocityspace)TQofitsconfigurationspaceQtothecotangentbundle(phasespace)T∗Q,otherdistinctionscanberaised,astowhetherthesymmetrytrans-formationinvelocityspaceisprojectabletophasespaceand,intheaffirmativecase,whetherthetransformationinphasespaceiscanonical.Wewillconsidertime-independentLagrangians,asitistheusualcaseinphysicaltheories,butwewillallowtodealwithtime-dependentfunc-tionstocoveralsogaugesymmetries(symmetriesdependinguponarbitraryfunctionsoftime,orspace-timevariablesinfieldtheory);thenwewilluseR×TQandR×T∗QinsteadofTQandT∗Q.
Theinfinitesimalsymmetriesofanordinarydynamicalsystemarecharacterizedbyaprop-ertyofcommutativity:essentially,thatthetimeevolutionoperatorcommuteswiththeoperatorthatgeneratesthesymmetry.
Canonical Noether symmetries and commutativity properties for ...
Lagrangian Quantum Field Theory in Momentum Picture: Free Fields
books.google.com.hk/books?isbn=160456170X - 翻譯這個網頁
Bozhidar Z. Iliev - 2008 - Science
In this book is considered only the Lagrangian (canonical) quantum field theory in which the quantum fields are represented as operators, called field operators,Canonical Noether symmetries and commutativity ... - 百度文库
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