Two-body experiment using only one laser source?

[Swamp Thing]

(a) Suppose we split a laser into two beams "A" and "B". Is it at all possible to do something to one of the beams, so that, when we bring them back to overlap at the detector(s), they will follow the statistics of two-photon systems?

(b) If we use two separate lasers that are phase-locked by external means, will they follow two-photon statistics if they overlap around the detectors?

The kind of staistics I am asking about is where you have detection amplitudes with terms like:
|a1> |b2> + |a2> |b1>.

 

[eljose79]

(a) It is possible to manipulate one of the beams in a way that will result in two-photon statistics when they are brought back to overlap at the detector(s). This can be achieved by using a nonlinear crystal to convert one beam into two beams with half the frequency of the original beam. This process is known as spontaneous parametric down-conversion (SPDC) and results in two entangled photons with opposite polarizations. When these two beams are overlapped at the detector, they will exhibit two-photon statistics.

(b) Using two separate lasers that are phase-locked by external means will not necessarily result in two-photon statistics when they overlap around the detectors. This is because the two lasers are still producing independent photons with no entanglement between them. However, if the two lasers are carefully tuned to produce photons with opposite polarizations, then they can exhibit two-photon statistics when overlapped at the detectors. This is known as quantum interference and is a result of the photons being indistinguishable from each other.