Precision Measurements of Scattering Phase Shifts in a Juggling Atomic Clock

这项实验研究计划将在原子钟中精确地研究超冷铯原子的量子散射。该小组展示了一种新型的散射实验，在超低温下，铯原子的两个时钟态以相干叠加的方式散射出纯态的原子。每个钟态都经历了S波的散射相移，并且通过只检测每个原子的波函数的散射部分，散射相移的差异可以直接观察到拉姆齐条纹的相移。一个独特的特点是，观测到的散射相移的差异与原子密度无关。这项技术为散射测量提供了原子钟精度，并有望显著提高我们对与激光冷却铯原子钟相关的原子相互作用的了解。该小组将对铯的不同内态随磁场的散射进行精确测量。这些实验将毫不含糊地限制并帮助精确地确定超低温铯-铯之间的相互作用，这些作用仍然不够清楚。由于超冷散射导致的原子钟的频移，特别是在极低能量的微重力下的原子钟，需要更好地了解相互作用。该计划的广泛影响包括培训一名研究生，掌握激光、电光、射频和微波技术、超高真空、原子钟和频率控制等许多现代技术领域的知识。这项工作将通过高精度的测量影响对超冷原子-原子相互作用的理解，为激光冷却微重力时钟提供关于超冷铯相互作用的重要信息。这些信息将有助于建立和提高在建的天基激光冷却原子钟的精度。

This experimental research program will precisely study the quantum scattering of ultracold cesium atoms in an atomic clock. The group has demonstrated a new type of scattering experiment that scatters a cesium atom in a coherent superposition of its two clock states off atoms in a pure state at ultracold temperatures. Each clock state experiences an s-wave scattering phase shift and, by detecting only the scattered part of each atom's wavefunction, the difference of the scattering phase shifts is directly observed as a phase shift of Ramsey fringes. A unique feature is that the observed difference of the scattering phase shifts is independent of the atomic density. The technique provides atomic clock accuracy to scattering measurements and is expected to significantly improve our knowledge of atomic interactions that are relevant for laser-cooled cesium clocks.The group will perform precision measurements of the scattering of different internal states of cesium as a function of magnetic field. These experiments will constrain unambiguously and help to determine precisely the ultracold cesium-cesium interactions that are still insufficiently known. Better knowledge of the interactions is required for the frequency shifts of atomic clocks due to ultracold scattering, especially at the very low energies of cesium clocks in microgravity.Broader impacts of this program include the training of a graduate student in many areas of modern technology from lasers, electro-optics, radio-frequency and microwave techniques, ultra-high vacuum, and atomic clocks and frequency control. The work will impact the understanding of ultracold atom-atom interactions with highly precise measurements, giving important information about the ultracold cesium interactions for laser-cooled microgravity clocks. This information will help establish and improve the accuracy of a space-based laser-cooled atomic clock under construction.