Frequency downconversion and ghost imaging: Classical and quantum approaches

. Ghost imaging is a phenomenon that attracted many physicists from the community in the last years, due to the different configurations by which it can be realised, but principally due to the wide discussion about its quantum or classical nature. Here we analyse a ghost imaging scheme realised in frequency downconversion, which is intrinsically a quantum interaction, from a classical point of view and, by means of a computer simulation, we also show that this description holds provided that the seed field is bright enough.