Overview
- An international team from the University of Ulm, the University of Oxford and Ben‑Gurion University used a device called the Quantum Galileo Interferometer to put ultracold rubidium atoms into a superposition and let one branch fall while the other was held in place.
- The researchers recombined the two branches and measured a tiny phase shift that matched the value Einstein’s equivalence principle predicts for free fall.
- The experiment used microwave pulses, an atom chip and precisely tuned magnetic fields to suspend one part of the atomic wave and let the other drop, giving direct access to the quantum phase difference accumulated during fall.
- The result does not unify quantum mechanics and gravity or prove gravity is quantum, but it establishes an empirical baseline and experimental tools for follow‑up tests with larger, more massive superpositions.
- Beyond this lab milestone, the work opens a clear path to experiments that could probe proposals that quantum mechanics breaks down for bigger objects and could reshape precision tests of gravity using quantum sensors.