  We study a generalization of the original Einstein-Podolsky-Rosen thought
experiment. It is essentially a delayed choice experiment as applied to
entangled particles. The basic idea is: given two observers sharing
position-momentum entangled photons, one party chooses whether she measures
position or momentum of her photons after the particles leave the source. The
other party should infer her action by checking for the absence or presence of
characteristic interference patterns after subjecting his particles to certain
optical pre-processing. An occurance of apparent signaling is attributed to the
difficulty in treating single photons simultaneously at a quantum mechanical
and quantum electrodynamic level, as required by the experiment, and points to
the need for a careful study of an aspect of the foundations of quantum
mechanics and electrodynamics.
