Certainly you can see the interference pattern once the superposition principles holds for the wave function of these particles. So you have the crossed term when making psi^2.
It's not what we are discussing. We are discussing if two photons can have the same quantum state. Two or more...
Maybe I'm wrong but you can see QM is absolutely epistemological just looking at the math. One could think that once the answer you have from asking (measuring) one system (at the quantum level) means nothing. As the answer comes as an eigenvalue of this operator related to the measuring, you...
Maybe I'm wrong, but I think you can deduce from this statement the main idea behind the the bose-einstein and fermi-dirac statistics. That's shortly why you don't have the exclusion principle for bosons.
Please don't mix the photon with the superposition principle acting in the...