A two-dimensional ultracold gas of fermionic polar LiCs molecules

本项目的目的是产生费米子LiCs分子的偶极量子气体，以研究远程偶极相互作用影响下的少体和多体效应。LiCs在旋转振动基态的偶极矩为5.5 Debye。如此大的偶极矩非常适合于探索强偶极相互作用的影响，例如在偶极晶体、自旋模型和超固相中发生的作用。为了研究这些现象，费米子极性分子的气体将通过光学限制在二维几何结构中来稳定非弹性碰撞损失，从而允许控制少体化学反应，并对潜在的少体碰撞过程进行全面的理解。超冷分子的产生是基于在光学偶极子阱中6Li和133Cs的双简并混合原子气体中产生弱束缚的fishbach分子和随后的STIRAP到旋转振动基态。偶极相互作用将由微波电场控制。在本研究计划的过程中，我们将开发通过极性分子的蒸发冷却来增加相空间密度的策略。极性分子稳定气体与强偶极相互作用能的结合，使探索平衡和非平衡条件下的偶极量子气体成为可能。

The aim of this project is to produce a dipolar quantum gas of fermionic LiCs molecules to study few- and many-body effects under the influence of long-range dipolar interaction. LiCs features a dipole moment of 5.5 Debye in the rovibrational ground state. Such a large dipole moment is ideally suited to explore the effects of strong dipolar interactions, as occurring for example in dipolar crystals, spin models, and super solid phases. In order to investigate these phenomena, the gas of fermionic polar molecules will be stabilized against inelastic collisional loss by optically confining it in a 2D geometry allowing for the control over the few-body chemical reactions and for the development of a comprehensive understanding of the underlying few-body collisional processes. The creation of the ultracold molecules is based on the production of weakly bound Feshbach molecules in a double-degenerate mixed atomic gas of 6Li and 133Cs in an optical dipole trap and subsequent STIRAP to the rovibrational ground state. The dipolar interaction will be controlled by microwave electric fields. In the course of this research program we will develop strategies for an increase of the phase space density by evaporative cooling of polar molecules. The combination of a stabilized gas of polar molecules and strong dipolar interaction energy makes it possible to explore the dipolar quantum gas under equilibrium and out-of-equilibrium conditions.