First excited Efimov state created

Nature : An Efimov state is a stable but fragile combination of three identical neutral atoms held together via the van der Waals force . Its existence was first confirmed in 2006 by Rudolf Grimm of the Institute for Experimental Physics in Innsbruck, Austria, and his colleagues. Now the same team of researchers has found an excited energy level for the molecule. The original work involved cooling cesium gas to 10 nanokelvin and using magnetic fields to push the atoms together. To produce the excited state, the group cooled the cesium gas even further and held the atoms in place with IR lasers. Altering the magnetic field changed the interaction energy of the atoms and allowed them to escape the laser trap. At a particular level of the magnetic field, the number of atoms escaping at high speed increased significantly, which indicates that an Efimov state had formed and then broken down. That observation closely matched the predicted behavior of the excited state of the Efimov configuration.