Biggest Schrödinger’s Cat

Why It Matters

Demonstrating superposition in a 7,000‑atom system narrows the gap between quantum theory and everyday matter, paving the way for advanced quantum technologies and deeper insight into the quantum‑classical boundary.

Key Takeaways

• Researchers created superposition with 7,000-atom cluster for quantum experiments.
• Superposition observed via interference pattern through nanogap screen.
• Experiment required -196°C temperature and ultra‑high vacuum conditions.
• Demonstrates quantum behavior persists at mesoscopic scales far beyond previous limits.
• Opens path toward superposing living organisms like bacteria.

Summary

Physicists have pushed the quantum frontier by coaxing a cluster of roughly 7,000 sodium atoms into a superposition of locations, creating what they dub the "biggest Schrödinger’s cat" to date. The experiment, conducted in a cryogenic chamber at –196 °C and ultra‑high vacuum, fired these mesoscopic particles at a nanogap screen and recorded a clear interference pattern, confirming wave‑like behavior despite the cluster’s size.

The result hinges on preserving delicate quantum states; even a stray air molecule would collapse the superposition. By demonstrating that a 7,000‑atom aggregate can traverse multiple paths simultaneously, the team shows that quantum mechanics does not abruptly give way to classical physics at the previously assumed microscopic boundary. The interference fringes serve as a direct visual cue that the atoms behaved as a coherent wave rather than independent particles.

The work echoes Erwin Schrödinger’s famous thought experiment, where a cat’s fate is linked to a quantum event. Here, the “cat” is a cloud of atoms, and the researchers have shown it can be both here and there until measured. They envision scaling the technique to larger, potentially living systems—perhaps a bacterium—thereby probing the long‑standing question of where the quantum‑classical transition truly lies.

If successful, such macroscopic superpositions could reshape quantum‑technology roadmaps, offering new platforms for precision sensing, quantum computing, and tests of fundamental physics. Understanding the decoherence threshold will inform how to protect quantum information in real‑world devices, making the experiment a pivotal step toward harnessing quantum effects at scales previously thought impossible.

Original Description

You may have heard of Schrödinger's cat, but did you know it represents one of the thorniest problems in quantum physics? Where is the boundary between the quantum and classical worlds? This recent experiment from a team at the University of Vienna successfully observed superposition in the largest object yet: a cluster of 7000 sodium atoms.

- Presented by Lizzie Gibney

- Produced by Maren Hunsberger

- Stock Footage from Getty Images / Sefa Kart

- Stock Images from Getty Images / Eleonora Galli and Adobe / macondos

- Music from Triple Scoop Music / Richard Ames

- Supervising Producer: Shamini Bundell

From Pedalino, S. et al. Nature. (2026). https://doi.org/10.1038/s41586-025-09917-9