Gauge transform
= Gauge transform
{wiki=Gauge_theory#Classical_gauge_theory}
Multiplication by $e^{ia\psi(x)}$ is a gauge transform that preserves pointwise modulus and mass while shifting the gradient by $ia(\nabla\psi)u$.
= Gauge transform
{wiki=Gauge_theory#Classical_gauge_theory}
Multiplication by $e^{ia\psi(x)}$ is a gauge transform that preserves pointwise modulus and mass while shifting the gradient by $ia(\nabla\psi)u$.