Abstract:

In 2012, the group of Ralf Menzel in Potsdam, Germany published an article in PNAS that appeared to violate the accepted quantum mechanical notion of complementarity.  Specifically, they observed interference with good fringe visibility in a Young's two-slit experiment, even though, through use of a quantum protocol, they were able to deduce through which slit each photon had passed.  Our group has recently articulated an explanation for these unexpected results (Bolduc et al., PNAS 2014).  Our explanation is that the Potsdam group had inadvertently violated a fair-sampling assumption by means of the manner in which they collected and analyzed their data.