Electron waves being shot past a tiny toroidal magnet.

 the Aharonov-Bohm effect. Predicted by theorists Yakir Aharonov and David Bohm in 1959, the effect is a phenomenon where electrons can be affected by electromagnetic potentials without coming in contact with actual force fields.

“It’s what is called ‘action-at-distance,’” said Batelaan, an associate professor of physics and astronomy. “An example of action-at-a-distance would be that you push with your finger in mid-air one foot above your table and a book that is lying on the desk moves. That would be weird — and so is any action-at-a-distance phenomenon.”

picture: Electron waves being shot past a tiny toroidal magnet.