Evidence for universal four-body states tied to an Efimov trimer.
We report on the measurement of four-body recombination rate coefficients in an atomic gas. Our results obtained with an ultracold sample of cesium atoms at negative scattering lengths show a resonant enhancement of losses and provide strong evidence for the existence of a pair of four-body states, which is strictly connected to Efimov trimers via universal relations. Our findings confirm recent theoretical predictions and demonstrate the enrichment of the Efimov scenario when a fourth particle is added to the generic three-body problem.
Ferlaino
F
F
Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, 6020 Innsbruck, Austria.
Knoop
S
S
Berninger
M
M
Harm
W
W
D'Incao
J P
JP
Nägerl
H-C
HC
Grimm
R
R