The fuzziness of the quantum world has been demonstrated on its largest-ever scale, probing the limits of quantum mechanics. More than a billion atoms inside a glass bead acted as a single quantum wave, a crucial step in making macroscopic matter interfere with itself and testing theories of quantum gravity.
In the early 20th century, physicists realised that, at tiny scales, matter appeared to be fuzzy. Although previous experiments had shown that particles like electrons or atomic nuclei were solid, new experiments demonstrated that…