Surprising new communication between atoms

The ultrahigh vacuum chamber where rubidium atoms are laser cooled and excited. Credit: Deniz Yavuz

Physicists at University of Wisconsin–Madison have identified conditions under which relatively distant atoms communicate with each other in ways that had previously only been seen in atoms closer together.

This work opens up new prospects for generating entangled atoms, a development that could have applications to quantum computing.

The scientists wanted to see how greater distances between the atoms would affect the decay of rubidium atoms. If the prevailing idea were correct, then two rubidium atoms further apart than 780 nanometers would act like individual atoms, each giving the characteristic single-atom decay profile.

In their experiments, they first immobilized a group of rubidium atoms by laser-cooling them to just slightly above absolute zero, the temperature at which atomic motion ceases. Then, they shined a laser at rubidium’s excitation wavelength to energize electrons, which decay while emitting a photon at the characteristic 780 nm. They could then measure the intensity of that emitted photon over time and compare it to the decay profile of a single rubidium atom. (

The study has been published in Physical Review A.

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