There’s only three possible angular momenta a photon can have.
First, two and not three, the spin projection 0 disappears for massless fields. Second, those are basis states, any normalized linear combination is also allowed. Third, they are talking about orbital angular momentum, not spin (I am unsure about the details, though).
Also, what kind of equipment would be necessary to use that?
They show their helix-shaped satellite dish, doesn’t seem overly high-tech.
Not correct! The Hilbert space for spin angular momentum has dimension 2 (-1, +1; left, right; up, down). The Hilbert space for orbital angular momentum has a denumerably infinite dimension (..., −3, 2, −1, 0, 1, 2,3 , …).
Not sure what you are arguing with so emphatically. DanielLC’s statement “Photons have spin 1.” implies spin, not orbital angular momentum, and the Hilbert space for photon spin is indeed 2D, as both you and I said.
First, two and not three, the spin projection 0 disappears for massless fields. Second, those are basis states, any normalized linear combination is also allowed. Third, they are talking about orbital angular momentum, not spin (I am unsure about the details, though).
They show their helix-shaped satellite dish, doesn’t seem overly high-tech.
Not correct! The Hilbert space for spin angular momentum has dimension 2 (-1, +1; left, right; up, down). The Hilbert space for orbital angular momentum has a denumerably infinite dimension (..., −3, 2, −1, 0, 1, 2,3 , …).
Not sure what you are arguing with so emphatically. DanielLC’s statement “Photons have spin 1.” implies spin, not orbital angular momentum, and the Hilbert space for photon spin is indeed 2D, as both you and I said.