Nuclear T-violation searches using ultracold atoms and molecules

宇宙中物质-反物质不对称性的起源是基础物理学中最深刻的公开问题之一。这种不对称性被认为是由微观时间反演对称破坏（T破坏）发生在极高的能量尺度。虽然这样的能量超出了目前对撞机的能力范围，但原子核可以作为这种新物理学的“天线”，通过精确测量它们的核对称性来揭示线索。核T破坏的测量可以通过使用保持在超冷温度（在微开尔文制度）下的激光冷却和捕获的原子和分子来实现对新物理的极高灵敏度。测量还受益于使用八极形变核，如225 Ra，其对核T破坏具有很大的固有灵敏度。在极性分子内的原子核的扩散甚至进一步增强了可测量的物理效应，这是由于电子施加到原子核上的大电场。 这里描述的研究计划旨在通过利用所有这些因素来开发世界领先的核T破坏实验。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捕获在可重新配置的光镊阵列中：捕获的原子导致更高精度的测量，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的测量精度。该计划还将（B）研究使用含有八极变形核的极性分子，这些分子可以在极低的温度下由激光冷却的原子组装而成：超冷分子组装提供了一条通往捕获分子生产的既定途径。这三种成分--八极形变核、极性分子和光阱阵列中的量子纠缠--的结合将开辟一条实验之路，与现有技术相比，对T-破坏的灵敏度将提高千倍以上。这项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，并将其应用于一项特定的基础物理任务：以前所未有的灵敏度测量核T破坏。这将是世界上第一个此类项目。这将使我的团队能够吸引优秀的学生和博士后，并培养一批在精密亚原子物理学的最新技术方面受过独特培训的技术人才。该研究计划旨在发现基本的科学真理，但其在高科技前沿的地位也使其肯定会导致技术副产品。该研究计划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，为推进亚原子物理学产生新的想法。

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.