Quantum gases with tunable interactions in optical lattices and photoassociation of molecules in optical lattices

我们计划在这个“schwerpunktprogram”的第二个资助期内实现两个主要的实验研究目标。基于我们在光学晶格中的玻色-爱因斯坦凝聚体方面非常成功的工作，我们将专注于在光学晶格势中创造85Rb凝聚体。在85Rb中，广泛的费什巴赫共振将使我们能够在很宽的范围内调整原子的散射长度，从而完全控制原子之间的相互作用参数。因此，我们不仅可以通过光学晶格势深度来调节不同晶格位置之间的隧道耦合，而且可以控制相互作用参数，从而完全控制基本的玻色-哈伯德哈密顿量中的所有参数。一个可控的现场相互作用参数将是非常有用的，以便通过简单地改变原子之间的相互作用来研究莫特绝缘体相变，并且还将允许我们通过具有更高的，然后更容易分辨的能量尺度来光谱地解决许多相互作用相关的效应。我们工作的第二个重点将是通过相干双光子光关联过程在光学晶格中创建超冷分子。用两个原子填充Mott绝缘体的点阵位，可以在三重态或单线态分子基态电位中诱导出高度有效的结合-结合光缔合过程。

We are planning to pursue two main experimental research goals within the second funding period of this "Schwerpunktprogramm". Building on our highly successful work on Bose-Einstein condensates in optical lattices, we will focus our work on the creation of a 85Rb condensate in an optical lattice potential. In 85Rb a broad Feshbach resonance would allow us to tune the scattering length of the atoms over a wide range and thereby have complete control over the interaction parameters between the atoms. We therefore would not only be able to tune the tunnel coupling between different lattice sites through the optical lattice potential depth, but also control the interaction parameter and thereby gain complete control over all parameters in the fundamental underlying Bose-Hubbard Hamiltonian. A controllable onsite interaction parameter would be very useful in order to study the Mott insulator phase transition by simply changing the interactions between the atoms and would also allow us to resolve many interaction related effects spectroscopically by having a higher and then more easily resolvable energy scale given by U. A second focus of our work will be directed towards the creation of ultracold molecules in optical lattices via coherent two-photon photoassociation processes. By filling lattice sites from a Mott insulator with two atoms one could induce a highly effective bound-bound photoassociation process to vibrational states in the triplet or singlet molecular ground state potential.