Can Matter be Created or Destroyed?

[Rhondazvous]

Yes, pair creation happens all the time at colliders such as the Large Hadron Collider (you do know my LHC thread, right?

http://atheistforums.org/thread-33518.html
)
If you want to know what photons do in pair creation, it is useful to look at the corresponding feynman graphs.



Basically, according to current understanding,  the photons exchange a virtual electron and this results in an electron and a positron to be created. Quantum electrodynamics simply postulates the interactions between the electron/positron and photon fields, no deeper underlying mechanism of interaction between them is known. In superstring theory, which is speculative, various models give a more detailed account how the conversion happens - such as end points of strings changing from one higher dimensional "brane" to another and thus changing the particle type.

Anyways, the nucleus in such experiments usually merely provides a counter mass which can absorb/emit a photon for the process. The precise details of the nucleus are usually unimportant, what you need is some massive thing with an electric charge.

Wow! That does explain a lot. I'm looking at the graph. The photons go in and come out as e+ and e-. Is the nucleus right there in the center where the photons meet (please correct me if they don't actually meet but just come close when they exchange the virtual electron)? Is the virtual electron taken from the nucleus?

No, I did not know about your LHC thread. I knew you were very knowledgeable about things quantum, but had no idea you were dealing specifically with pair production. My plot calls for the production of positrons specifically. So that would be more like the VEPP 2000 than the LHC. Still, this calls for a big acknowledgement in the final publication.