Are neutral atoms really neutral? A new experiment could look for tiny charges as low as 10–28 e, beating present limits by eight orders of magnitude, according to Asimina Arvanitaki and colleagues at Stanford University. The idea is to use lasers to split a beam of cold rubidium atoms into a superposition of two momentum states and then see how they interact with electric fields that could slightly slow down one component with respect to the other if a charge were present. A phase shift could give away the presence of a tiny charge. The effect sounds bizarre, but it is actually anticipated by some theorists.