Inside a vacuum chamber at the University of Vienna, scientists achieved something remarkable. A small piece of sodium containing between 5,000 and 10,000 atoms was sent through a tunnel of laser light. For about one hundredth of a second, it existed in two places at the same time.
This discovery, published in the journal Nature, represents the largest object ever placed into a quantum superposition state in a laboratory. The metal cluster was roughly 8 nanometres across and weighed more than 170,000 atomic mass units. According to the laws of quantum mechanics, objects this large should behave like ordinary matter and exist in only one place.
The experiment used a new instrument called MUSCLE, which uses three diffraction gratings made of laser light instead of solid material. When the sodium cluster passed through, its quantum wave split into multiple paths and then recombined, creating an interference pattern that proved superposition had occurred.
The lead researcher was Sebastian Pedalino, a doctoral student working under Markus Arndt and Stefan Gerlich. Their team measured a value called macroscopicity that was roughly ten times higher than any previous record. This breakthrough pushes scientists closer to understanding whether quantum mechanics has limits at larger scales. The research team plans to continue their work by attempting to place even larger biological particles, such as viruses or proteins, into the same impossible state.