- #1
karlzr
- 131
- 2
In scalar QED, there are two noether currents ##J_{global}## and ##J_{local}##corresponding to the global and local gauge transformations respectively.
In QED, the two currents are exactly the same. But in scalar QED, they are totally different.
$$J_{global}^\mu=i e (\phi^\dagger \partial^\mu\phi-\phi\partial^\mu\phi^\dagger)$$ and
$$J_{local}^\mu=i e (\phi^\dagger D^\mu\phi-\phi D^\mu\phi^\dagger)$$
where ##D^\mu## is covariant derivative. So my question is how to interpret these two quantities? which one represents the charge of the scalar field?
In QED, the two currents are exactly the same. But in scalar QED, they are totally different.
$$J_{global}^\mu=i e (\phi^\dagger \partial^\mu\phi-\phi\partial^\mu\phi^\dagger)$$ and
$$J_{local}^\mu=i e (\phi^\dagger D^\mu\phi-\phi D^\mu\phi^\dagger)$$
where ##D^\mu## is covariant derivative. So my question is how to interpret these two quantities? which one represents the charge of the scalar field?