Science a GoGo's Home Page Forums General Discussion General Science Discussion Forum entanglement

On and off for a long time I have read about entanglement. Everywhere I look to read about it I find the theory and explantations. However, I can never find out exactly how two systems can be made to become entangled. Can anyone help me out with this problem. Thanks in advance for any help.

True: " However, I can never find out exactly how two systems can be made to become entangled. Can anyone help me out with this problem. Thanks in advance for any help."

Roughly speaking, to make two systems entangled, you need to have interactions between them, such that one cannot distinguish the properties of any one of the two systems anymore in the properties of the entangled system. Think of a molecule, say the hydrogen molecule, H2. Quantum mechanically the behavior of the molecule is different from the behaviour of two individual atoms.

This is, in general terms, how you can see entanglement.

How can you practically make entangled systems? It depends. You can create a pair of entangled photons through a pair generation process, molecules you can create in the usual way (chemical reactions) or through forced collisions for odd and/or unstable compounds, and the list could go on and on and on.

They don't become entangled, they are created engangled. Example: A single photon enters a nonlinear optical medium and is split into two half-frequency entangled photons that exit. If the original photon was linearly polarized you are set for the Bell Inequality and the Einstein-Podolsky-Rosen paradox.

Shoot a photon into a 45-degree half-silvered mirror. There ya go, Bunky, entanglement until you look for where it went.

Thank you very much Pasti and Uncle Al. I have been under the impression that entanglement was some kind of action at a distance thing between two systems that were originally unrelated after having some kind of interaction. I can look at it in a different way now.

There's an entertaining if lowbrow look at entanglement here http://www.abc.net.au/science/features/quantum/ which may be of assistance.

Question : can anyone here understand that entanglement is seen clearly in the cooper pair electrons of superconductivity, as 2 fermions<normally repelling> being tethered on the ends of a MATTER WAVE, and this gives us a vital clue as to what bose-bonding/capacitance GRAVITY is?

Thanks Kate. That's an interesting link.