Can an optical physicist comment on how the phase-shifting is accomplished? What do they mean by "phase"? (I would have expected this to mean polarization phase, but this chip seems to be based not on polarization but on relative phase shift?)<p>Also, that CNOT gate is… weird. How can post-selecting scale, if each CNOT gate in the circuit reduces the chance of a successful run by 89%?<p>Another also, the interpretation of the CNOT gate given in the tutorial seems reversed – photon mode 1 corresponds to control input <i>1</i>; mode 2 corresponds to control input <i>0</i>, at least according to the simulator.