  Contrary to the Bohr complementarity principle, in 1995 Rabinowitz proposed
that by using entangled particles from the source it would be possible to
determine which slit a particle goes through while still preserving the
interference pattern in the Young two slit experiment. In 2000, Kim et al used
spontaneous parametric down conversion to prepare entangled photons as their
source, and almost achieved this. In 2012, Menzel et al. experimentally
succeeded in doing this. When the source emits entangled particle pairs, the
traversed slit is inferred from measurement of the entangled particle location
by using triangulation. The violation of complementarity breaches the
prevailing probabilistic interpretation of quantum mechanics, and benefits the
Bohm pilot wave theory.
