Noether current for a spacetime symmetry
ID: noether-current-for-a-spacetime-symmetry
For and , the fixed-coordinate field variation is . Suppose action invariance is expressed as . Writing and , the product rule gives . Thus is a conserved current on shell. A vanishing spatial boundary flux is additionally required for its Noether charge to be conserved. This formula includes internal transformations, translations and Lorentz transformations.
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