A tiny lump of metal just pulled off a trick that defies everyday logic: it existed in two places at the same time.
Physicists at the University of Vienna in Austria have shattered the record for the largest object ever placed into a quantum superposition. The object was a nanoparticle made of thousands of sodium atoms, roughly 8 nanometers wide. It behaved as if it were in multiple locations at once, a hallmark of quantum mechanics normally reserved for electrons, atoms, and small molecules.
A chunk of metal that acts like a wave
The experiment, published in Nature, was led by Markus Arndt and Stefan Gerlich. The team created ultracold sodium clusters containing between 5,000 and 10,000 atoms. Each cluster had a mass exceeding 170,000 atomic mass units, making them heavier than most proteins. The researchers then shot these particles through three diffraction gratings made of ultraviolet laser beams.
The first laser beam pinned down each cluster's position with an accuracy of about 10 nanometers. Then it placed the particle into a quantum superposition, meaning it could follow multiple paths through the apparatus at the same time. The result was a measurable interference pattern, the telltale sign that the metal lump was behaving like a wave, not a solid object.
Why this matters for the boundary between quantum and classical
In daily life, rocks, marbles, and dust follow classical physics. They stay in one place and move along predictable paths. But the Vienna team showed that even a relatively large chunk of metal still obeys the bizarre rules of the quantum world. Lead author Sebastian Pedalino, a doctoral student, said the result proves that quantum mechanics holds at this scale and does not require alternative models.
The finding pushes quantum weirdness closer to the macroscopic world. It suggests that the boundary between quantum and classical behavior may not be as sharp as once thought. For now, the metal lump remains the heaviest object ever to exist in two places at once, a record that challenges our intuition about what is possible.
