We recently investigated the effect of the pump coherence on the position-momentum entanglement in spontaneous parametric down conversion. For this, we actually used an LED to generate pairs. They are perfectly correlated in position (as they are “born” at the same place) but do not have any correlation in momentum, which seems to contradict momentum conversion?! If you want to know why this is not the case and how one can control this type of entanglement by adjusting the pump coherence, check out our recent paper published in Optics Express.
Congrats to all co-authors and in particular Wuhong Zhang for the great work.