How are you interpreting this experiment with DeBroglie-Bohm? This is bumping up into the area where the theory gets into trouble, as photons aren't described b

How are you interpreting this experiment with DeBroglie-Bohm? This is bumping up into the area where the theory gets into trouble, as photons aren't described by the Schrodinger equation or Dirac equation, and don't have wave functions at all. However in interferometry you might talk about the wave function of a photon if it is not emitted or absorbed. Re: Locality. The issue is not nearly as simple as you are making it out to be. You are not allowed to naively dispense with locality because locality, described quantitatively by Lorentz invariance, is one of the most well tested physical principles in the history of science. You don't get to ignore observations to conform to your philosophical biases regarding interpretations of your theories. The principles of special relativity and quantum mechanics are combined in quantum field theory, which is the most accurate and well tested description of the world we currently have. Non-relativistic Quantum Mechanics (where debroglie bohm is nice and simple) is a (0+1) dimensional quantum field theory, whereas our universe is described by (3+1) dimensional quantum field theories like quantum electrodynamics or the standard model. To dispense with locality in a non-naive way requires extending the theory to this more complicated setting, which is an unsolved problem, and an active are of research. According to the wikipedia page, even developing a complete theory of the photon is an active area of research! Whereas developing QED the first time around only took a handful of people 15 years...and they didn't know what the answer was going to turn out to be! I think we can conclude from this that the theory is no longer so simple and easy to grasp.