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

我们计划在“Schwerpunktprogramm”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玻色-爱因斯坦凝聚体方面非常成功的工作，我们将把工作重点放在光学晶格势中85 Rb凝聚体的创建上。在85 Rb中，一个宽的Feshbach共振将允许我们在很宽的范围内调节原子的散射长度，从而完全控制原子之间的相互作用参数。因此，我们不仅能够通过光学晶格势深度调整不同晶格位置之间的隧道耦合，而且还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，以便研究莫特绝缘体相变，通过简单地改变原子之间的相互作用，也将允许我们解决许多相互作用相关的影响光谱通过有一个更高的，然后更容易分辨的能量标度由U。我们工作的第二个重点将是通过相干双光子光缔合过程在光学晶格中产生超冷分子。通过用两个原子填充莫特绝缘体的晶格位点，可以诱导一个高效的束缚-束缚光缔合过程，使其在三重态或单重态分子基态势中振动。

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.