Nuclear T-violation searches using ultracold atoms and molecules

宇宙中物质-反物质不对称的起源是基础物理学中最深奥的开放性问题之一。这种不对称被认为是由发生在极高能量尺度上的微观时间反转对称违逆（t违逆）引起的。虽然这种能量超出了目前对撞机所能达到的范围，但原子核可以充当这种新物理的“天线”，通过对原子核对称性的精确测量揭示线索。通过使用激光冷却和捕获处于超冷温度（微开尔文状态）的原子和分子，核t违逆的测量可以达到对新物理的极高灵敏度。使用八极子形变核（如225Ra）也有利于测量，因为它对核t违逆具有很大的固有灵敏度。由于电子对原子核施加了巨大的电场，在极性分子中加入原子核进一步增强了可测量的物理效应。这里描述的研究计划旨在通过利用所有这些因素来开发一个世界领先的核t违反实验。它将利用原子和分子物理学的许多最新技术。该计划将(a)使用激光冷却的原子，这些原子被困在一个可重构的光镊阵列中：被困的原子导致更高的精度测量，而在镊子阵列中的原子可以被置于纠缠态，以提高使用量子相关性测量的精度。该计划还将(b)研究含有八极子变形核的极性分子的使用，这种分子可以在极低的温度下由激光冷却的原子组装而成：超冷分子组装为生产被困分子提供了一条既定的途径。这三种成分的结合——八极子变形核、极性分子和光学陷阱阵列中的量子纠缠——将为实验开辟一条道路，与目前的技术水平相比，对t违逆的灵敏度要高1000倍以上。本研究计划将利用原子物理和量子信息科学领域的最新发展，并将其应用于特定的基础物理任务：以前所未有的灵敏度测量核t违逆。这个项目将是世界上第一个这样的项目。这将使我的小组能够吸引优秀的学生和博士后，并产生一批在精密亚原子物理最新技术方面受过独特训练的技术人员。该研究项目旨在发现基本的科学真理，但它在高科技前沿的地位也使它肯定会带来技术衍生品。该研究项目还将对原子物理学和量子信息科学产生重大的科学反作用，为亚原子物理学的发展产生新的思想。

The origin of the matter-antimatter asymmetry of the universe is one of the deepest open questions in fundamental physics. This asymmetry is believed to arise from microscopic time-reversal symmetry violation (T-violation) occuring at extremely high energy scales. Although such energies are beyond the present reach of colliders, atomic nuclei can act as "antennas" for this new physics, revealing clues through precision measurements of their nuclear symmetries. Measurements of nuclear T-violation can achieve extremely high sensitivity to new physics by using laser-cooled and trapped atoms and molecules held at ultracold temperatures (in the micro-kelvin regime). The measurements also benefit by using octupole-deformed nuclei such as 225Ra, which have a large intrinsic sensitivity to nuclear T-violation. Incorporating the nuclei within a polar molecule enhances the measurable physics effects even further, due to the large electric fields applied to the nuclei by the electrons. The research program described here aims to develop a world-leading nuclear T-violation experiment by taking advantage of all of these factors. It will leverage many of the latest techniques from atomic and molecular physics. This program will (a) use laser-cooled atoms trapped in a reconfigurable array of optical tweezers: trapped atoms lead to higher precision measurements, and atoms in tweezer arrays can be placed in entangled states to boost the precision of measurements using quantum correlations. The program will also (b) investigate the use of polar molecules containing octupole-deformed nuclei, which can be  assembled from laser-cooled atoms at extremely low temperatures: ultracold molecular assembly offers an established path towards production of trapped molecules,. The combination of these three ingredients -- octupole-deformed nucleus, polar molecule and quantum entanglement in an optical trap array -- will open a path to experiments with more than thousand-fold higher sensitivity to T-violation compared to the state of the art. This research program will take advantage of the latest developments in the fields of atomic physics and quantum information science, and apply them to a specific fundamental physics task: measuring nuclear T-violation with unprecedented sensitivity. This program will be the first of its kind in the world. It will enable my group to attract excellent students and postdocs, and generate a cohort of skilled personnel with unique training in the latest techniques of precision subatomic physics. The research program aims to discover fundamental scientific truths, but its position at the high-technology frontier also makes it certain that it will lead to technological spin-offs. The program of research will also have a substantial scientific back-action on atomic physics and quantum information science, generating new ideas to advance subatomic physics.