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?

For more than a century, the double-slit experiment has been the sharpest test of what reality is made of, and of whether Albert Einstein or Niels Bohr had the better grasp of the quantum world. Now a ...

MIT physicists have performed an idealized version of one of the most famous experiments in quantum physics. Their findings demonstrate, with atomic-level precision, the dual yet evasive nature of ...

Does quantum mechanics allow the future to retroactively influence the past or not? Does quantum mechanics allow the future to retroactively influence the past, as in the infamous delayed choice ...

Quantum entanglement is a fundamental phenomenon in nature and one of the most intriguing aspects of quantum mechanics. It describes a correlation between two particles, such that measuring the ...

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 ...