We study the diffraction of atoms and weakly-bound three-atomic molecules from a transmission grating at non-normal incidence. Due to the thickness of the grating bars the slits are partially shadowed. Therefore, the projected slit width decreases more strongly with the angle of incidence than the projected period, increasing, in principle, the experimental resolution. The shadowing, however, requires a revision of the theory of atom diffraction. We derive an expression in the style of the Kirchhoff integral of optics and show that the diffraction pattern exhibits a characteristic asymmetry which must be accounted for when comparing with experimental data. We then analyze the diffraction of weakly bound trimers and show that their finite size manifests itself in a further reduction of the slit width by (3/4)<r> where <r> is the average bond length. The improved resolution at non-normal incidence may in particular allow to discern, by means of their bond lengths, between the small ground state of the helium trimer (<r>=1 nm, Barletta and Kievsky, Phys. Rev. A 64, 042514 (2001)) and its predicted Efimov-type excited state (<r>=8 nm, ibid.), and in this way to experimentally prove the existence of this long-sought Efimov state.
Efimov Trimer Formation via Ultracold Four-body Recombination
我们讨论了Efimov三聚体通过超冷四体复合的碰撞形成。特别地，我们考虑了A+A+A+B-> A ~ 3 +B与A和B超冷原子的反应。我们得到的四体复合率的表达式，并表明，它反映了三体Efimov物理无论是作为碰撞能量的函数，或作为一个函数的两体s-波散射A原子之间的长度。此外，我们简要地讨论了重要的实验观察这个有趣的和相对未开发的过程的问题。
Universality of weakly bound dimers and Efimov trimers close to Li-Cs Feshbach resonances
研究了超冷Li-Cs混合物在磁场为800 G ~ 1000 G时两个自旋能量最低的通道中的种间散射特性。接近两个广泛的费什巴赫共振，我们创建弱结合的锂离子二聚体的射频协会和测量的结合能对外部磁场强度的依赖性。基于Li-Cs的另外三个s波费什巴赫共振的结合能和互补原子损失谱，我们利用耦合通道计算方法构造了精确的分子单重态和三重态电子基态势。我们提取了Li-Cs物种间散射长度作为外场的函数，并且与我们以前的工作相比，在s波Li-Cs费什巴赫共振的极点位置和宽度的值的精度方面获得了几乎十倍的改进[Pires \textit{et al.}，Phys. Rev. Lett. \textbf{112}，250404（2014）]。我们讨论的Efimov方案和通用的几何缩放LiCsCs三聚体的影响。
Supersymmetric isospectral formalism for the calculation of near-zero energy states: application to the very weakly bound ${^4}$He trimer excited state
