In a device such as an optical display, positive (purple) and negative (gold) charges are attracted strongly to one another and become trapped (first picture). Because of the unusual rules of quantum physics, the trapped charges can emit light (second picture) if they are spinning in opposite directions. Van Voorhis is creating simulations to show how to selectively create trapped charges in organic light-emitting diode displays to improve efficiency. Image courtesy / Troy Van Voorhis