CAREER: Precision Measurements with Ultracold Diatomic Molecules

非技术性描述：对“现在几点了？“最终可以追溯到基于原子内部滴答声的主时钟。 提高这些主时钟的精度在过去已经实现了我们在汽车和智能手机中使用的GPS系统等创新，以确定我们在地球仪上的位置。 未来时钟的改进有望实现类似的创新，而这些创新才刚刚开始被想象。 目前的项目旨在通过使用分子而不是原子更精确地跟踪时间来扩展我们可以实现的科学和技术的范围。分子提出了量子钟的可能性，它基于与原子钟不同的物理学：核振动而不是电子跃迁。由两个原子组成的简单分子将在接近绝对零度的温度下产生，并被困在驻波光中，以确保与环境几乎完全隔离。 这些锶分子具有非常明确的内部能量状态，允许用激光进行精确操纵和探测。这个时钟对宇宙演化过程中可能发生的电子与质子质量比的变化以及可能出现在纳米尺度上的尚未发现的力都很敏感。 技术说明：主要研究者的研究小组最近展示了一类基于激光冷却锶原子的新型超冷双原子分子。 这项工作（基于这些二聚体的光学捕获，操纵和成像）将使分子物理学的精确测量以及基本定律的测试成为可能，这些基本定律可能表明标准模型之外的新物理学。 最初的工作表明，通过应用原子晶格钟技术，这个分子在激发态和基态，可以进行直接测量的非绝热科里奥利混合角的分子波函数，这些角度是描述弱分子键合附近的原子连续的关键。 本计画将进一步描述这些弱束缚系统从绝热到非绝热的转变。 此外，紧密结合的超冷基态锶二聚体将用于振动光谱学或分子振动时钟。 如果能更好地理解货车德瓦尔斯型原子间相互作用的质量标度，这个时钟可能会提高几个数量级的纳米级质量相关力的知识。 当该分子的晶格光谱的系统效应被更好地表征并且作为该项目的一部分优化了状态不敏感的晶格捕获时，该分子钟可以对电子与质子质量比的稳定性设置最佳的模型独立限制。 坚固的分子钟在大地测量、导航和基础科学测试中有应用。特别努力让来自当地纽约市社区的年轻公立学校学生参与进来，让他们接触科学家的日常工作。

Non-technical description:The answer to the question "what time is it?" ultimately traces back to master clocks that are based on the internal ticking of atoms. Increasing the accuracy of these master clocks has in the past enabled such innovations as the GPS systems that we use in our cars and smartphones to locate our position on the globe. Future improvements in clocks can be expected to enable similar innovations that are only just beginning to be imagined. The present project seeks to extend the scope of the science and technology we can achieve by keeping track of time ever more accurately, using molecules instead of atoms. Molecules present the possibility of a quantum clock based on different physics than atomic clocks: nuclear vibrations rather than electronic transitions. Simple molecules that consist of two atoms will be created near the temperature of absolute zero and trapped in standing waves of light to ensure nearly complete isolation from the environment. These strontium molecules possess very well defined internal energy states that allow precise manipulation and probing with laser light. This clock is sensitive to variations in the electron-to-proton mass ratio that may occur as the universe evolves, and to yet undiscovered forces that might appear at nanometer scales. Technical description:A new class of ultracold diatomic molecules based on laser-cooled strontium atoms was recently demonstrated by the primary investigator's research group. This work (based on optical trapping, manipulation, and imaging of these dimers) will enable precision measurements in molecular physics as well as tests of fundamental laws that may indicate new physics beyond the Standard Model. Initial work indicates that by applying atomic lattice-clock techniques to this molecule in both the excited and ground states, a direct measurement of the nonadiabatic Coriolis mixing angles of the molecular wavefunctions can be performed; these angles are critical for describing weak molecular bonding near the atomic continuum. This project will further characterize the transition from adiabatic to nonadiabatic behavior in these weakly bound systems. Additionally, tightly bound ultracold ground-state strontium dimers will be created for vibrational spectroscopy, or a molecular vibrational clock. If the mass scaling of the van der Waals type interatomic interaction is better understood, this clock can potentially improve the knowledge of nanometer-scale mass-dependent forces by several orders of magnitude. When the systematic effects of lattice spectroscopy of this molecule are better characterized and state-insensitive lattice trapping is optimized as part of this project, this molecular clock can set the best model-independent limit on the stability of the electron-to-proton mass ratio. Robust molecular clocks have applications in geodesy, navigation, and tests of fundamental science. Special efforts are made to involve young public school students from local New York City neighborhoods and expose them to the day-to-day work of scientists.