- #1
jtceleron
- 16
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This question is from K. Huang, Quantum Field Theory: from operators to path integrals.
He says that, under a continuous infinitesimal transformation,
\phi(x)->\phi(x)+\delta\phi
the change of the Lagrangian density must be in the from
\deltaL=∂^{\mu}W_{\mu}(x)
It is easily understood that this quantity must be Lorentz-invariant, but why should only be this form, not others (e.g. without derivatives).
He says that, under a continuous infinitesimal transformation,
\phi(x)->\phi(x)+\delta\phi
the change of the Lagrangian density must be in the from
\deltaL=∂^{\mu}W_{\mu}(x)
It is easily understood that this quantity must be Lorentz-invariant, but why should only be this form, not others (e.g. without derivatives).