Amy Nelson, a senior fellow at New America, explains that minimal deterrence may still be possible in a multipolar world, but ...

In 1927, Albert Einstein and Neils Bohr debated the nature of what’s known as complementarity—the idea that a photon’s dual wave-like and particle natures can’t be measured at the same time. Now, two ...

A century-old thought experiment on wave–particle duality is brought into the laboratory using a single trapped atom ...