Two clumps of matter pass through each other without sharing space; In some cases the colliding clumps of matter appear to deepen their distance even as they pass through each other. Clumps of a few hundred thousand lithium atoms that are cooled to within one-millionth of a degree above absolute zero a temperature so cold that the atoms march in lockstep and act as a single matter wave. The Interaction of light with matter has long been a field of interest for many quant...