Laurent Sébastien, Pierce Matthieu, Delehaye Marion, Yefsah Tarik, Chevy Frédéric, Salomon Christophe
Laboratoire Kastler Brossel, ENS-PSL Research University, CNRS, UPMC-Sorbonne Universités, Collège de France, 24 rue Lhomond, 75005 Paris, France.
Phys Rev Lett. 2017 Mar 10;118(10):103403. doi: 10.1103/PhysRevLett.118.103403.
We study three-body recombination in an ultracold Bose-Fermi mixture. We first show theoretically that, for weak interspecies coupling, the loss rate is proportional to Tan's contact. Second, using a ^{7}Li/^{6}Li mixture we probe the recombination rate in both the thermal and dual superfluid regimes. We find excellent agreement with our model in the BEC-BCS crossover. At unitarity where the fermion-fermion scattering length diverges, we show that the loss rate is proportional to n_{f}^{4/3}, where n_{f} is the fermionic density. This unusual exponent signals nontrivial two-body correlations in the system. Our results demonstrate that few-body losses can be used as a quantitative probe of quantum correlations in many-body ensembles.
我们研究了超冷玻色-费米混合物中的三体复合。我们首先从理论上表明，对于弱种间耦合，损失率与谭接触成正比。其次，我们使用(^{7}Li/^{6}Li)混合物在热态和双超流态下探测复合率。我们发现在玻色-爱因斯坦凝聚-BCS交叉区域与我们的模型有很好的一致性。在费米子-费米子散射长度发散的幺正极限下，我们表明损失率与(n_{f}^{4/3})成正比，其中(n_{f})是费米子密度。这个不寻常的指数表明系统中存在非平凡的两体关联。我们的结果表明，少体损失可以用作多体系综中量子关联的定量探针。
