Quantum Physics: virtual particles are not nothing (General)

by David Turell , Tuesday, January 24, 2017, 14:53 (2858 days ago) @ dhw

QUOTE: "Now, using a trick of quantum optics as astonishing as it is weird, physicists from the University of Konstanz in Germany have found a way to manipulate nothingness by controlling how virtual particles interact with a pulse of light."

David’s comment: The scientists made the virtual particle appear at their will. They are obviously not nothing but appear from a 'somewhere' we still do not understand. I presented this article to make my point, but the new results are an outstanding advance to help study the universe.

dhw: Your comment is very helpful, as you seem as puzzled as I am. Please can you explain what they mean by “virtual”. As an ignorant layman, I take it to mean “not real” (as in man-made computer games). If the particles are not “real” and not man-made, how can they be controlled and how can they interact with reality? And if they can be controlled and can interact with reality, what is “nothing”?

I am proud to inform you that I spent 33 years teaching at the University of Konstanz (as one of the very first generation of tutors) – but not in the physics department!

Since you taught English, I'll try to explain the physics concept: 'virtual' means the particles pop into and out of our reality of existence. Where they come from and where they go is the unknown issue addressed by Ruth Kastner. They are not unreal if they can be herded! Evanescent might be a better term for them. Whew!