Metal clumps in a quantum state: Physicists place thousands of sodium atoms in a 'Schrödinger's cat state'

Physicists demonstrated quantum superposition in macroscopic metal clusters, placing sodium nanoparticles—each containing thousands of atoms—into a Schrödinger’s cat-like state spanning distant locations. The breakthrough confirms quantum rules apply at unprecedented scales. The experiment, published in Nature, was conducted by teams at the University of Vienna and the University of Duisburg-Essen. It marks one of the most rigorous tests of quantum mechanics in large, complex systems. Researchers used sodium nanoparticles, each massive by quantum standards, to probe the boundary between quantum and classical physics. The particles exhibited coherent quantum behavior despite their size. This work challenges the notion that quantum effects fade in macroscopic objects, reinforcing that even "bulky" systems can exist in superposition. It opens doors for testing quantum-classical transition theories. The findings could advance quantum sensing and fundamental physics, offering new ways to explore gravity’s role in quantum collapse and the limits of superposition in large systems.