In the late 1970s, legendary physicist John Wheeler proposed a radical question: Exactly when does the universe notice that we're paying attention to a quantum experiment? And does it really matter?

Physicists confirm that light has two identities that are impossible to see at once. (Nanowerk News) MIT physicists have performed an idealized version of one of the most famous experiments in quantum ...

Schematic of the MIT experiment: Two single atoms floating in a vacuum chamber are illuminated by a laser beam and act as the two slits. The interference of the scattered light is recorded with a ...