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有趣的物理现象，从超流性的基础研究到强相关的多体系统。随着这一领域的成熟，人们对制造类似的分子气体的兴趣越来越大，丰富的内部结构提供了新的、迷人的物理学。最有希望获得这些财富的途径之一是利用将原子气体冷却到简并的能力，然后将成对的原子结合形成双原子分子。在这种情况下，异质结分子的形成是特别感兴趣的，因为在基态下，分子表现出永久的电偶极矩，产生长程各向异性相互作用。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，其中一个规则阵列的相互作用的分子限制在一个三维的光学晶格是用来模拟问题，更通常与凝聚态物理。该项目的目标是探索使用超冷分子（RbCs或CsYb）的量子模拟协议的实验实现。在RbCs的情况下，我们的研究将研究使用分子的旋转状态来编码伪自旋以模拟量子磁性，而在CsYb的实验中可以利用未成对电子的自旋。新的工作将集中在1D，2D和3D的光学晶格的发展。最终，我们将开发方法来探测分子在单晶格网站的水平，以便深入了解复杂的多体动力学的晶格。

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 molecules - either RbCs or CsYb. In the case of RbCs, our studies will investigate the use of rotational states of the molecule to encode a pseudo spin for simulation of quantum magnetism, whereas in CsYb experiments can exploit the spin of the unpaired electron. New work will focus on the development of 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.