  The ghost interference observed for entangled photons is theoretically
analyzed using wave-packet dynamics. It is shown that ghost interference is a
combined effect of virtual double-slit creation due to entanglement, and
quantum erasure of which-path information for the interfering photon. For the
case where the two photons are of different color, it is shown that fringe
width of the interfering photon depends not only on its own wavelength, but
also on the wavelength of the other photon which it is entangled with.
