Another entaglement question

[nateHI]

I'm watching a series of lectures on QM and the last one dealt with entaglement. You can see it here (http://www.youtube.com/watch?v=IAgV-LKTiMI&feature=channel) if you want. I understand it in the purely theoretical sense. It's a very neat concept.

Naturally, my next question is, how would you physically entangle two electrons? What is the experimental set up for adding angular momentum or spin operators of two separate Hilbert spaces?

[Feldoh]

Typically people use spontaneous parametric down-conversion. Basically you send photons through a non-linear crystal structure. Every once in a which a photon will split into two photons going in different directions. The energy and momentum and spin, etc of the two new photons are conserved and equal to the value of the initial photon so they are entangled.