Are photons in the laser output beam mutually independent and can the multi-photon output be described as the tensor product of individual photon states?
That's not quite what I meant but it's conceptually close. I just don't understand how the photons can be statistically independent.
If it's a sum over Fock states, then the exact number of photons in the output must be indeterminate. But if it's indeterminate, doesn't that imply that we cannot write the output state as a product of photon states?
So if I understood correctly, in a real laser the photons are not completely independent since one cannot suppress spontaneous emission?
If that's the case, should we describe the multi-photon output as an entangled state, or does entanglement only apply when we have a fixed number of photons?
"the inverse of the laser beta factor which can be as large as 1000000:1 or above"
That's true. My question was if mutual dependence between output photons exists in principle.
Suppose this number is small (let's say, N=1 emitter to take the extreme case). How would we then write the resulting output state?