Closed-loop cryocooler for continuing an ongoing research on helium nanodroplets

需求和紧迫感。我正在进行的研究活动之一，始于2017年，是通过光学离心机这一独特工具对超流氦内部分子动力学的量子控制。该项目需要一个低温冷却器，这是我从一位同事(UBC/化学公司的Takamasa Momose博士)那里借来的。莫莫斯博士需要在2020年初拿回他的冷冻机(他的信附在这份申请表上)。如果我没有可用的制冷机，这个项目将停滞不前，迫使一名博士和一名硕士学生在关键时刻改变他们的研究主题，因为第一批初步结果终于在最新的实验中出现。2014年，我所在的UBC研究小组建造了一台独特的激光仪器--光学离心机，并用它来创造和研究新的、奇特的分子物体，被称为“分子超级旋翼”。超旋翼是一种超快旋转的分子，其相干旋转由激光场控制。我们的离心机是世界上三台之一，也是加拿大唯一的一台。它也是世界上唯一一台可以直接控制和测量分子超旋的三个基本参数的离心机，其频率、方向性和相位。离心机使我们能够进行许多分子研究，这在任何其他研究实验室都是不可能的。到目前为止，我们已经研究了分子超级转子的性质，在这个区域，量子关联和多体物理并不重要。最近，我开始将这项研究扩展到研究嵌入多体量子系统中的分子的旋转动力学，使用受控激光旋转氦纳米液滴中的分子。70多年前，通过机械控制的旋转顶在宏观尺度上探测到了超流现象。由于缺乏可控的微型转子，在纳米尺度上进行类似的研究被证明是不可能的。光学离心机使这些研究成为现实，我的团队处于领先地位。*知识和培训的进步。量子超流体中分子旋转的受控激活将为我们提供一个研究旋转物体与复杂量子系统相互作用的动力学的机会。对这种动力学的更好理解将对未来量子技术的发展产生直接影响，预计这将给安全通信、生物系统的计算机分析以及对电场、磁场和引力场的微小变化的传感带来革命性的变化。氦纳米液滴长期以来一直被认为是理想的纳米晶体，因为它们能够在透明和非反应的环境中冷却单个分子。除了量子研究，它们还用于光谱学、化学物理和生物学研究。学习和使用这项低温技术的机会将为我的学生提供一项非常重要的技能，这是在其他任何地方都很难获得的。

NEED and URGENCY. One of my ongoing research initiatives, started in 2017, is on quantum control of molecular dynamics inside superfluid helium by means of a unique tool of an optical centrifuge. The project requires a cryogenic cooler, which I have been borrowing from a colleague (Dr. Takamasa Momose at UBC/Chemistry). Dr. Momose will need his cooler back at the beginning of 2020 (his letter is attached to this application). Without the cryocooler available to me, the project will stall, forcing one PhD and one MSc student to change their research topic at a critical time, when first preliminary results have been finally emerging in the latest experiments.******RESEARCH PROGRAM. In 2014, my UBC research group has built a unique laser instrument an “optical centrifuge”, and used it to create and study new and exotic molecular objects, known as “molecular super-rotors”. Super-rotors are ultrafast rotating molecules whose coherent rotation is controlled by the laser field. Our centrifuge is one of three in the world and the only one in Canada. It is also the only centrifuge worldwide in which the three fundamental parameters of molecular “super-rotation” its frequency, directionality and phase can be controlled and measured directly. The centrifuge enabled us to carry out a number of molecular studies, impossible in any other research laboratory. Until now, we have investigated the properties of molecular super-rotors in the regime, where quantum correlations and many-body physics are of little importance. Recently, I started expanding this research to studying rotational dynamics of molecules embedded in many-body quantum systems using controlled laser spinning of molecules inside helium nanodroplets. More than 70 years ago, superfluidity was probed on a macroscopic scale by a mechanically controlled rotating top. Similar studies at the nanoscale proved impossible due to the lack of controllable microscopic rotors. An optical centrifuge makes these studies a reality, and my group is ideally positioned to take the lead.******ADVANCEMENT of KNOWLEDGE and TRAINING. Controlled activation of molecular rotation inside quantum superfluids will provide us with an opportunity to study the dynamics of a rotating object interacting with complex quantum systems. Better understanding of such dynamics will have direct impact on the development of future quantum technologies, which are expected to revolutionize secure communications, computer analysis of biological systems, and sensing of small changes in electrical, magnetic and gravitational fields. Helium nanodroplets have long been recognized as ideal nanocryostats due to their ability to cool single molecules inside their transparent and non-reactive environment. Aside from quantum studies, they are used in spectroscopy, chemical physics and biology research. Opportunities to learn and use this cryogenic technology will provide my students with a very important skill, which is hard to acquire anywhere else.*****