Towards quantum simulation with ultracold polar molecules

超冷和量子简并原子气体已被用于研究大量新颖而有趣的物理现象，从超流体的基础研究到强相关的多体系统。随着这一领域的成熟，人们对产生类似分子气体的兴趣日益浓厚，这种气体丰富的内部结构为研究新的、迷人的物理学提供了途径。获得这些财富的最有希望的途径之一是在原子对结合形成双原子分子之前，利用原子气体冷却到简并的能力。在这种情况下，异核分子的形成是特别有趣的，因为在基态下，分子表现出永久的电偶极矩，从而产生远距离各向异性相互作用。这种相互作用极大地改变了气体在超冷温度下的行为，并找到了许多应用。一个这样的应用是在量子模拟领域，其中一个规则的相互作用分子阵列被限制在三维光学晶格上，用于模拟通常与凝聚态物理有关的问题。该项目的目标是探索使用超冷红细胞分子的量子模拟协议的实验实现。我们的研究将探讨利用分子的旋转状态来编码伪自旋来模拟量子磁性。我们将扩展现有的实验装置，包括1D， 2D和3D的光学晶格。最终，我们将开发在单点阵位水平上探测分子的方法，以深入了解点阵中复杂的多体动力学。

Ultracold and quantum degenerate atomic gases have been exploited to study a vast array of novel and interesting physical phenomena ranging from fundamental studies of superfluidity to strongly-correlated many body systems. As the field has matured there has been a growing interest in the quest to produce similar gases of molecules, where the rich internal structure offers access to new, fascinating physics. One of the most promising routes to these riches is to exploit the ability to cool atomic gases to degeneracy before associating pairs of atoms to form diatomic molecules. In this context the formation of heteronuclear molecules is of particular interest as, in the ground state, the molecules exhibit a permanent electric dipole moment that gives rise to long-range anisotropic interactions. Such interactions dramatically modify the behaviour of the gas at ultracold temperatures and find many applications. One such application is in the area of quantum simulation where a regular array of interacting molecules confined on a three dimensional optical lattice is used to simulate problems more usually associated with condensed matter physics. The goal of this project is to explore experimental implementations of quantum simulation protocols using ultracold RbCs molecules. Our studies will investigate the use of rotational states of the molecule to encode a pseudo spin for simulation of quantum magnetism. We will extend the current experimental apparatus to include optical lattices in 1D, 2D and 3D. Ultimately we will develop methods to probe the molecules at the level of single lattice sites in order to gain insight into the complex many-body dynamics in the lattice.