Story perspectives

Quantum atoms confirm equivalence principle with gravity cancelation

9/8/2026

Summary

Story summary

Ron Folman’s Israeli team demonstrated the equivalence principle on quantum atoms.
They used ultracold rubidium atoms near an atom chip to create a superposition.
A magnetic force held one atom cloud stationary, cancelling gravity.
A magnetic flick lifted a second cloud, which fell and recombined, producing interference.
Measured phase shifts matched Einstein’s equivalence-principle predictions, as noted by co-author Vlatko Vedral (University of Oxford).

History

Historical Context

Robert Colella, Ernest Overhauser and Samuel Werner’s 1975 COW neutron-interferometer experiment sent neutrons over a 10-cm height difference, observing a 0.2-radian phase shift that confirmed gravity’s influence on quantum particles. This test follows a tradition of laboratory verification, exemplified by Stephen Babcock’s 1907–1911 single-grain nutrition study at the University of Wisconsin. The 2024 atom-chip work by Folman’s team and Vlatko Vedral extends that lineage toward quantum-gravity integration.

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Story summary

Ron Folman’s Israeli team demonstrated the equivalence principle on quantum atoms.
They used ultracold rubidium atoms near an atom chip to create a superposition.
A magnetic force held one atom cloud stationary, cancelling gravity.
A magnetic flick lifted a second cloud, which fell and recombined, producing interference.
Measured phase shifts matched Einstein’s equivalence-principle predictions, as noted by co-author Vlatko Vedral (University of Oxford).

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