Quantum Trimer - From a Distance

Some years ago, Rudolf Grimm's team of quantum physicists in Innsbruck provided experimental proof of Efimov states - a phenomenon that until then had been known only in theory. Now they have also measured the second Efimov resonance of three particles in an ultracold quantum gas, thus, proving the periodicity of this universal physical phenomenon experimentally. Eight years ago Rudolf Grimm's research group was the first to observe an Efimov state in an ultracold quantum gas. The Russian physicist Vitali Efimov theoretically predicted this exotic bound state of three particles in the 1970s. He forecast that three particles would form a bound state due to their quantum mechanical properties, under conditions when a two-body bound state would be absent. What is even more astounding: When the distance between the particles is increased by factor 22.7, another Efimov state appears, leading to an infinite series of these states. Until now this essential ingredient of the famous scenario has remained elusive and experimentally proving the periodicity of the famous scenario has presented a challenge.