Researchers have harnessed quantum entanglement to link atoms across space, achieving unprecedented accuracy in measuring physical quantities. By separating entangled atomic clouds, the team improved the detection of electromagnetic fields. This breakthrough could refine atomic clocks and gravity sensors.
A collaboration between scientists at the University of Basel and the Laboratoire Kastler Brossel in Paris has demonstrated a novel use of quantum entanglement for enhanced precision measurements. Entanglement, a quantum phenomenon where particles remain connected despite separation, defies classical physics and was spotlighted in the 2022 Nobel Prize for confirming the Einstein-Podolsky-Rosen paradox.
Led by Prof. Dr. Philipp Treutlein and Prof. Dr. Alice Sinatra, the researchers entangled the spins of ultracold atoms—tiny magnetic-like properties—and split them into up to three distinct clouds. This allowed measurements of varying electromagnetic fields with reduced quantum uncertainty and cancellation of common disturbances.
"We have now extended this concept by distributing the atoms into up to three spatially separated clouds," Treutlein noted, building on his group's work from about 15 years ago when they first entangled atoms at a single site. Postdoc Yifan Li highlighted the innovation: "So far, no one has performed such a quantum measurement with spatially separated entangled atomic clouds, and the theoretical framework for such measurements was also still unclear."
The method starts by entangling spins in one cloud before dividing it, enabling high-precision field mapping with few measurements. PhD student Lex Joosten explained potential applications: "Our measurement protocols can be directly applied to existing precision instruments such as optical lattice clocks," where atoms in laser lattices act as ultra-accurate timekeepers. It could also enhance atom interferometers in gravimeters, which detect subtle gravity variations.
Published in Science (2026, vol. 391, issue 6783, p. 374), the study by Yifan Li, Lex Joosten, Youcef Baamara, Paolo Colciaghi, Alice Sinatra, Philipp Treutlein, and Tilman Zibold advances quantum metrology, an established field exploiting quantum effects for better sensing.