Department of Physics and Astronomy and Rice Quantum Institute, Rice University, Houston, TX 77005, USA.
Science. 2009 Dec 18;326(5960):1683-5. doi: 10.1126/science.1182840. Epub 2009 Nov 19.
Under certain circumstances, three or more interacting particles may form bound states. Although the general few-body problem is not analytically solvable, the so-called Efimov trimers appear for a system of three particles with resonant two-body interactions. The binding energies of these trimers are predicted to be universally connected to each other, independent of the microscopic details of the interaction. By exploiting a Feshbach resonance to widely tune the interactions between trapped ultracold lithium atoms, we find evidence for two universally connected Efimov trimers and their associated four-body bound states. A total of 11 precisely determined three- and four-body features are found in the inelastic-loss spectrum. Their relative locations on either side of the resonance agree well with universal theory, whereas a systematic deviation from universality is found when comparing features across the resonance.
在某些情况下，三个或更多相互作用的粒子可能形成束缚态。尽管一般的三体问题无法解析求解，但对于具有共振两体相互作用的三体系统，会出现所谓的埃弗雷特三聚体。这些三聚体的束缚能被预测为彼此普遍相关，与相互作用的微观细节无关。通过利用费什巴赫共振来广泛调节被俘获的 ultracold 锂原子之间的相互作用，我们发现了两个普遍相关的埃弗雷特三聚体及其相关的四体束缚态的证据。在非弹性损耗谱中总共发现了 11 个精确确定的三体和四体特征。它们在共振两侧的相对位置与普遍理论非常吻合，而当比较共振两侧的特征时，会发现系统地偏离了普遍性。
