But the exact nature of light, and how it travels, has long puzzled scientists. One question in particular has vexed thinkers from Issac Newton to Albert Einstein: Is light a particle or a wave?

Take, for instance, quantum entanglement, which says that the state of one particle can be determined by examining the state of its entangled ... nonlocality,” where objects are influenced across ...

Take, for instance, quantum entanglement, which says that the state of one particle can be determined ... distances (seeming beyond the speed of light) whereas classical physics follows local ...

Light's quantum behavior is well established, with over 100 years of experiments showing it can exist in both wave and particle form. But our fundamental understanding of this quantum nature is ...