Helium liquefier system for research on ultracold molecules

超冷分子研究在过去五年中呈爆炸性增长，这是超冷原子研究的自然延伸，超冷原子研究始于25年前，基于激光冷却的技术突破。1微开尔文(英国)以下的超冷原子是一种全新的物质状态，已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。现在人们普遍认为，超冷分子比超冷原子具有更好的潜力来解决基础科学和应用科学中的各种物理和化学问题。它们的范围从自然界的基本对称性测试到星际化学，以及在量子计算中的应用。因此，超冷分子的集合是化学和物理学的新前沿的宝库，任何其他方法都是完全无法获得的。由于在1K以下仍然很难产生冷分子气体，我们的主要研究重点是开发一种新的制造超冷分子的技术，考虑到冷分子的广泛应用。在这个项目中，我们将建造一个液氦液化器及其回收系统，这是制造超冷分子气体装置必不可少的工具。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，以实现分子温度为1 UK。此外，该系统的设计目的是使装置的辐射屏蔽始终保持在4.2K，同时使新的氦气体损失最小，以避免超冷分子因黑体辐射而升温。目前，UBC还没有自己的液化器，因此，为了挑战UBC的超冷分子研究，建设一个氦液化系统是必不可少的。没有这个系统，就不可能在创造超冷分子方面取得突破，从而在这个新兴的研究领域获得主动权。所申请的资金将使UBC能够高效地研究冷系统，并将使UBC成为世界上领先的超冷分子研究中心。

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.