  We investigate the specific form that the collapsed quantum state of a signal
photon can take when its entangled idler is measured in an entangled ghost
imaging configuration using a type II collinear phase matched spontaneous
parametric downconversion (SPDC) interaction. Calculation of the correlated
counting rate distributions in the ghost image plane and diffraction plane show
that agreement between collapse and non-collapse models is obtained if the
signal is assumed to collapse into a specific mixed state. However, if the
signal is assumed to collapse into a pure state, significant differences arise
between the predictions of the two collapse models.
