Telecom-Band Rotational Cooling of a Heavy Molecular Ion

这个项目是为了开发一种简单而廉价的技术来使用激光来控制射频陷阱中分子离子的量子态。现代物理学研究的一个主旨是获得对日益复杂的物体的完全量子控制。这种控制的应用包括量子信息处理、量子控制的化学研究，以及在基本粒子和场的标准模型之外改进对暗物质和其他物理的搜索。利用激光控制被捕获原子的量子态已经取得了巨大的成功，但直到最近才有了控制被捕获分子的激光技术。在这个项目中，研究人员将首次使用廉价的电信波段激光器来光学控制一种新的分子离子--单电离氢化碲(Th)的量子态。这将开发基础物理研究所需的新技术，并将培养原子、分子和光学物理研究方法的研究生。除了具有允许电信波段光学控制的正确结构外，Te还具有天体物理意义，因为Te是测试恒星中重元素形成模型的探测器，事实上，它是在最近由LIGO联合探测到的千里诺瓦事件的光谱中观察到的。Th应该是太空中最丰富的含Te物种之一，但它作为标记的使用首先需要在实验室中观察其光谱。TH也是离子陷阱应用的一个有吸引力的物种，不仅因为它有可能进行廉价的状态控制，而且还因为它的固有性质。它比之前研究用于状态控制的大多数其他分子离子要重得多，在量子信息处理应用中具有较低的运动加热率，在精确测量中具有较小的二阶多普勒频移。此外，它还具有长寿命的振动态和深振动势垒，这使得它的高振动泛音跃迁吸引了质子-电子质量比随时间变化的光学频率探测器的候选者。在这项工作中，研究人员将在分子束中产生Th，并将对其光谱性质进行首次实验测量。然后，他们将在旨在优化简单性和成本或国家准备效率或速度的各种方案中展示旋转光泵。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project is for developing a simple and inexpensive technique to use lasers to control the quantum state of molecular ions held in radiofrequency traps. One thrust of modern physics research is to gain full quantum control over increasingly complex objects. Applications of such control include quantum information processing, quantum-controlled chemistry studies, and improved searches for dark matter and other physics beyond the Standard Model of elementary particles and fields. Great success has been achieved in using lasers to control quantum states of trapped atoms, but it is only recently that laser techniques to control trapped molecules have become available. In this project researchers will develop the first use of inexpensive telecom-band lasers to optically control the quantum states of a new species of molecular ion, singly-ionized Tellurium Hydride (TeH+). This will develop new technology needed for fundamental physics studies, and it will train graduate students in atomic, molecular and optical physics research methods.Besides having the right structure to allow telecom-band optical control, TeH+ is of astrophysical interest because Tellurium (Te) serves as a probe for testing models of heavy element formation in stars and was in fact observed in spectra from the recent kilonova event jointly detected by LIGO. TeH+ should be one of the most abundant Te-containing species in space, but its use as a marker first requires the observation of its spectrum in a laboratory. TeH+ is also an attractive species for ion trap applications, not only because of the potential for inexpensive state control, but also because of its intrinsic properties. Being significantly heavier than most other molecular ions previously investigated for state control, it would have lower motional heating rates in quantum information processing applications and smaller second-order Doppler shifts in precision measurements. Furthermore, TeH+ also has long-lived vibrational states and a deep vibrational well, making its high vibrational overtone transitions attractive candidates for optical-frequency probes of time-variation of the proton-electron mass ratio. In this work, the researchers will produce TeH+ in a molecular beam and will perform the first experimental measurements of its spectroscopic properties. They will then demonstrate rotational optical pumping in various schemes designed to optimize either simplicity and cost or state preparation efficiency or speed.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.