One of the most bizarre aspects of quantum physics is that the
fundamental entities that make up the Universe, what we know as the
indivisible quanta of reality, behave as both a wave and a
particle. We can do certain experiments, like firing photons at a
sheet of metal, where they act like particles, interacting with the
electrons and kicking them off only if they individually have enough
energy. Other experiments, like firing photons at small thin objects
— whether slits, hairs, holes, spheres, or even DVDs — give
patterned results that show exclusively wave-like behavior. What we
observe appears to depend on which observations we make, which is
frustrating, to say the least. Is there some way to tell,
fundamentally, what the nature of a quanta is, and whether it’s
wave-like or particle-like at its core?