Variational principle

A variational principle is a principle in physics which

Related Topics:
Variational principle - Physics

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is expressed in terms of the calculus of variations.

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According to Cornelius Lanczos, any physical law which can be expressed as a variational principle describes an expression which is self-adjoint. These expressions are also called Hermitian. Such an expression describes an invariant under a Hermitian transformation.

Related Topics:
Cornelius Lanczos - Self-adjoint - Hermitian - Invariant

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Felix Klein's Erlangen program attempted to identify such invariants under a group of transformations. In what is referred to in physics as Noether's theorem, the Poincaré group of transformations (what is now called a gauge group) for general relativity defines symmetries under a group of transformations which depend on a variational principle, or action principle.

Related Topics:
Felix Klein - Erlangen program - Noether's theorem - Poincaré group - Gauge group - General relativity - Action principle

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