A particle of light is all it takes to establish a quantum connection between nearly 3,000 atoms, scientists report in the March 26 Nature. The finding brings physicists a step closer to studying the macroscopic effects of quantum entanglement, which links the properties of microscopic particles.
MIT quantum physicist Vladan Vuletić and colleagues bounced photons between two mirrors in a space that contained about 3,100 rubidium atoms cooled to nearly absolute zero. Occasionally the polarization of a photon changed slightly, indicating that the photon had interacted with the atoms. Measurements revealed that each brief interaction coaxed at least 2,700 of the atoms to become entangled.
The researchers hope to use clusters of entangled atoms to build extraordinarily precise atomic clocks.