# Trying to visualize how a single photon can carry away more than one unit of angular momentum

I have a newbie question that I am trying to wrap my brain around.

Single photon gamma emission from a nucleus undergoing a $2^{+}$ to $0^{+}$ transition would involve an emitted photon with angular momentum of $2 \hbar$ in order for angular momentum to be conserved.

However, photons are spin one particles, so the above photon must have some orbital angular momentum in addition to its spin angular momentum.

I have difficulty visualizing how an unbounded, massless particle could have orbital angular momentum. Unless of course it were orbiting a black hole.

• Interesting. So the wavefunctions of photons with orbital angular momentum aren't simply just plane waves. The phase of the wavefunctions will have a sinusoidal dependence on the polar angle (in cylindrical coodinates) similar to the helical modes of light beams with orbital angular momentum. Integrating over these wavefunctions then gives a net angular momentum $l_{z}$ for the chosen direction. Therefore not dependent on the origin indicated for one's coordinate system. – dualredlaugh Jul 20 '16 at 3:32