Comment on “Biphoton double-slit experiment”

The de Broglie–Bohm sdBBd formalism of quantum mechanics f1–3g was initially proposed by Louis de Broglie in 1926, and finally formulated, in mathematical terms, by David Bohm in 1952. Since then, all attempts to prove a measurable difference with the Copenhagen interpretation, named here standard quantum mechanics sSQMd, have been unfruitful f1–3g. In a recent article f4g, experimental data for a two-bosons system impinging upon a double slit are compared with dBB predictions obtained by two different theoretical groups f5–9g. The authors conclude that their experimental data reproduces the SQM predictions and contradicts the dBB theory. In particular, they wrote: “Thus, if the theoretical prediction is confirmed, our result will represent the first negative test of the de Broglie–Bohm theory.” The goal of this Comment is to show that their experimental results do not provide any negative test of the dBB theory, but only verify a particular quantum-optical prediction. First, in Sec. II, we explain that the well-known particle conservation law of the dBB theory guarantees that Bohm trajectories exactly reproduce SQM observable results. Then, in order to provide an additional evidence, we show that Bohm trajectories reproduce SQM predictions for the particular two-entangled bosons system studied in Refs. f5–8g. Finally, in Sec. III, we discuss the differences between the wave function used to deduce the dBB predictions and the one used for obtaining SQM results.