Physicists observe 'Bethe strings' in a chain of ultracold atoms

Researchers at the University of Innsbruck have found evidence of Bethe strings — clusters of attracting atoms predicted by Hans Bethe in 1931. Chains of at least six cesium atoms formed inside one-dimensional laser tubes; the findings were published in Nature Communications.

• Clusters of at least six cesium atoms held in 1D laser tubes
• 3D clouds expanded with about three times the energy of 1D ones
• Measurements closely matched generalized hydrodynamics predictions
• About 40% of atoms were lost in the coldest runs