Helium liquefier system for research on ultracold molecules

作为25年前基于激光冷却技术突破而开始的超冷原子研究的自然延伸，超冷分子研究在过去五年中呈爆炸式增长。低于1微开尔文（uK）的超冷原子，一种全新的物质状态，已经被证明为研究物理学中广泛的基本问题提供了新的可能性。目前人们普遍认为，超冷分子比超冷原子在解决物理和化学基础科学和应用科学中的各种问题方面具有明显更好的潜力。它们的范围从对自然界基本对称性的测试到星际化学，以及对量子计算的应用。因此，超冷分子的集合是化学和物理学新领域的宝库，是任何其他方法都无法实现的。由于制造低于1k的冷分子气体仍然很困难，我们研究的主要重点是开发一种制造超冷分子的新技术，考虑到冷分子的广泛应用。在本项目中，我们将建设液氦液化器及其回收系统，这是建造制造超冷分子气体设备必不可少的工具。该系统产生的液氦将用于分子的预冷，这将遵循我们最初的想法对分子进行光学冷却，使分子的温度达到1 uK。此外，该系统旨在使仪器的辐射屏蔽始终保持在4.2 K，并尽量减少新型氦气的损失，以避免黑体辐射对超冷分子的加热。目前，UBC没有自己的液化器，因此，为了挑战UBC的超冷分子研究，氦气液化器系统的建设是必不可少的。没有这个体系，就不可能在超冷分子的创造上取得突破，从而在这个新兴的研究领域获得主动权。申请的资金将使UBC高效地研究冷系统，并将使UBC成为世界上研究超冷分子的领先中心。

Ultracold molecule research has grown explosively in the last five years as a natural extension of ultracold atom research, which began more than 25 years ago based on the technological breakthroughs in laser cooling. Ultracold atoms below 1 micro-kelvin (uK), completely novel states of matter, have been proved to offer new possibilities in studying a wide range of fundamental problems in physics. It is now widely accepted that ultracold molecules possess significantly better potential than ultracold atoms to address various problems in fundamental and applied sciences in both physics and chemistry. They range from test of fundamental symmetry in nature to interstellar chemistry, as well as application to quantum computation. Ensembles of ultracold molecules are therefore a treasury of new frontiers in both chemistry and physics, completely unavailable by any other means. Since it is still difficult to create cold molecular gases below 1 K, the primary focus of our research is on the development of a new technique of making ultracold molecules, having a broad range of applications of cold molecules in mind. In this project, we will construct a liquid helium liqueifier and its recovery system, which are essential and indispensable tools to build apparatuses for making ultracold molecular gases. Liquid helium produced by the system will be used for the pre-cooling of molecules, which will follow an optical cooling of molecules based on our original idea to achieve temperature of molecules at 1 uK. In addition, the proposed system is designed to keep radiation shields of the apparatus at 4.2 K all the time with minimum loss of novel helium gases in order to avoid warming of ultracold molecules by blackbody radiations. Currently, UBC does not posseses its own liquefier, so the construction of a helium liquefier system is indispensable to challenge the ultracold molecule research at UBC. Without the system, it is not possible to make breakthroughs in the creation of ultracold molecules to obtain initiative in this emerging research field. The requested funding would enable research on cold systems at UBC efficiently, and would make UBC a leading center in the world for the study of ultracold molecules.