Pairs of atoms observed existing in two places at once for the first time

Amazing stuff!

"... "This result confirms the predictions of over a century ago that matter can be in two locations at once, and it can interfere with itself even in those locations," ..."

From the abstract:

"Nonlocal entanglement between pair-correlated particles is a highly counter-intuitive aspect of quantum mechanics, where measurement on one particle can instantly affect the other, regardless of distance. 

While the rigorous Bell’s inequality framework has enabled the demonstration of such entanglement in photons and atomic internal states, no experiment has yet involved motional states of massive particles.

Here we report the experimental observation of Bell correlations in motional states of momentum-entangled ultracold helium atoms. Momentum-entangled pairs are first generated via s-wave collisions. Using a Rarity-Tapster interferometer and a Bell-test framework, we observe atom-atom correlations required for violation of a Bell inequality.

This result shows the potential of ultracold atoms for fundamental tests of quantum mechanics and opens new avenues to studying gravitational effects in quantum states."

Pairs of atoms observed existing in two places at once for the first time (This article was not very helpful!)

Spooky quantum helium atoms give hope for a Theory of Everything (original news release. However webpage did not open properly, see screenshot below)

Bell correlations between momentum-entangled pairs of 4He* atoms (open access)

Fig. 1: Schematic of the experimental procedure in momentum space.