An anonymous reader writes: From an article at ArsTechnica.com: "One of the deepest mysteries in quantum physics is the wave-particle duality: every quantum object has properties of both a wave and a particle. Nowhere is this effect more beautifully demonstrated than in the double-slit experiment: streams of particles (photons, electrons, whatever) are directed at a barrier with two narrow openings. [...] Now researchers have successfully performed a quantum interference experiment with much larger and more massive molecules than ever before. Thomas Juffmann et al. fired molecules composed of over 100 atoms at a barrier with openings designed to minimize molecular interactions, and observed the build-up of an interference pattern."