CAN AN EMPTY DEBROGLIE PILOT WAVE INDUCE COHERENCE

According to the de Broglie pilot wave theory, a pilot wave which is empty of photons is still capable of physical effects like induced coherence. We have carried out an experiment to test this prediction. The experiment involves interference of photons produced by down-conversion in two nonlinear crystals and depends on the mutual coherence induced between thc two signal beams by an idler. When the photon is removed from the idler by a beam splitter, it is found that the resulting "empty pilot wave" no longer induces coherence. This violates at least the Selleri-Croca version of the de Broglie pilot wave theory and makes the physical reality of the corresponding pilot wave doubtful.