  There has been considerable interest in a recent preprint - arXiv/1407.3194 -
describing an effect named as the Quantum Pigeonhole Principle. The classical
pigeonhole principle (classical PHP) refers to a result in number theory which
states that if n objects are distributed between m boxes, with m less than n,
then at least one box must contain more than one object. An experiment is
proposed in the preprint where interactions between particles would reveal that
they were in the same box, but a quantum mechanical measurement would imply
that no more than 1 of the n objects is contained in any of the m boxes, even
though n is greater than m. This result has been greeted by the authors of the
preprint and some others as being of great importance in the understanding of
quantum mechanics. In this paper we show by a full quantum mechanical treatment
that the effect appears to arise as a result of interference between the
components of the wavefunctions, each of which is subject to the classical PHP.
