Xie Xin, Van de Graaff Michael J, Chapurin Roman, Frye Matthew D, Hutson Jeremy M, D'Incao José P, Julienne Paul S, Ye Jun, Cornell Eric A
JILA, National Institute of Standards and Technology and the University of Colorado, and Department of Physics, Boulder, Colorado 80309, USA.
Joint Quantum Centre (JQC) Durham-Newcastle, Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom.
Phys Rev Lett. 2020 Dec 11;125(24):243401. doi: 10.1103/PhysRevLett.125.243401.
We study three-atom inelastic scattering in ultracold ^{39}K near a Feshbach resonance of intermediate coupling strength. The nonuniversal character of such resonance leads to an abnormally large Efimov absolute length scale and a relatively small effective range r_{e}, allowing the features of the ^{39}K Efimov spectrum to be better isolated from the short-range physics. Meticulous characterization of and correction for finite-temperature effects ensure high accuracy on the measurements of these features at large-magnitude scattering lengths. For a single Feshbach resonance, we unambiguously locate four distinct features in the Efimov structure. Three of these features form ratios that obey the Efimov universal scaling to within 10%, while the fourth feature, occurring at a value of scattering length closest to r_{e}, instead deviates from the universal value.
我们研究了在中等耦合强度的费什巴赫共振附近超冷(^{39}K)中的三原子非弹性散射。这种共振的非普适特性导致了异常大的埃菲莫夫绝对长度尺度和相对较小的有效范围(r_{e})，使得(^{39}K)埃菲莫夫光谱的特征能更好地与短程物理相分离。对有限温度效应的细致表征和校正确保了在大散射长度下对这些特征进行测量时的高精度。对于单个费什巴赫共振，我们明确地在埃菲莫夫结构中定位了四个不同的特征。其中三个特征形成的比率在10%的范围内符合埃菲莫夫普适标度，而第四个特征出现在最接近(r_{e})的散射长度值处，反而偏离了普适值。
