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?

A new discovery suggests gravitational fields can enable matter to become quantum entangled — and that's even if the concept of quantum gravity does not exist. The idea comes from two London-based ...

In the everyday world that humans experience, objects behave in a predictable way, explained by classical physics. One of the important aspects of classical physics is that nothing, not even ...

A pair of photons enters an optical maze, and sometimes they leave as something new. Not new in the everyday sense, since both were still photons when they came out.

Physicists have long suspected that gravity might have a hidden quantum side, but for decades the idea has been more mathematics than measurement. A new proposal for a tabletop experiment now suggests ...

A groundbreaking experiment demonstrates yet again that light exists both as a wave and a particle in the quantum world—but we can’t see both at the same time. Reading time 3 minutes Albert Einstein ...

Can a small lump of metal be in a quantum state that extends over distant locations? A research team at the University of Vienna answers this question with a resounding yes. In the journal Nature, ...

As physicists search for a theory of quantum gravity, new results show that classical gravity can still interact with quantum fields to allow matter to become entangled. When you purchase through ...