Sympathetic Cooling and Collisions of Atomic and Molecular Ions with Ultracold Atoms

交感冷却被困的原子和分子离子的研究，通过使用离子碰撞与第二（超冷）种中性原子（如钠），已预先被激光冷却到低于1/1000度以上的绝对零度。本研究的重点是非常低的能量离子-中性原子碰撞作为冷却机制，这是非常少的实验所知。经典（牛顿）和量子（薛定谔-海森伯）散射的边界以新的方式探索。 所研究的离子-中性相互作用是非常普遍的，涉及离子电场对中性伴侣的极化（电荷分离）;极化的中性原子然后反过来强烈吸引离子。 分子（和分子离子）很难直接用激光冷却，因此这项工作应该可以应用于太阳系和星际空间中的一般能量交换过程，控制零开尔文附近的离子-分子放热反应，在晶格中产生分子离子的维格纳晶体，离子的精密光谱学，超精密原子和分子离子时钟，并且可能，量子计算机或涉及捕获离子阵列的量子存储寄存器。该项目使用一种特殊的混合离子-中性阱（MOT和Paul阱组合）来重叠碱金属原子和各种离子（例如Ca+、Na 2+、Na+）的云，并允许观察冷却速率和由此发生的反应。这项基础研究涉及原子物理学、分子物理学、频率标准、空间物理学和天体物理学、量子信息和存储器及其许多应用。 康涅狄格大学的原子，分子和光学物理学（AMO）研究目前涉及10名活跃的教师和约38名研究生，他们通过个人研究，与同行互动，每周的研究研讨会和座谈会，学者访问，公开讲座和社区宣传，接受涉及所有这些领域的广泛教育。研究成果经常在会议上发表。PI的一个学生在本科量子力学的物理专业，现在参与了博士水平的研究这个项目。三名暑期本科生，沿着两名来自海德堡大学的交换生参与了该项目。鼓励本科生参加相关的独立研究项目。 该项目的学生接受基础实验物理技术的广泛教育，包括真空，激光冷却和捕获，光学，激光光谱学，离子操纵和检测等。

Sympathetic cooling of trapped atomic and molecular ions is investigated by using ion collisions with a second (ultracold) species of neutral atoms (e.g. sodium) which have previously been laser cooled to less than 1/1000th degree above absolute zero. This research focuses on very low energy ion-neutral atomic collisions as the cooling mechanism, about which very little is known experimentally. The boundaries of classical (Newtonian) and quantum (Schroedinger-Heisenberg) scattering are explored in new ways. The ion-neutral interaction under study is very general, involving the polarization (charge separation) of the neutral partner by the electric field of the ion; the polarized neutral atom then acts back to strongly attract the ion. Molecules (and molecular ions) are very difficult to laser cool directly, so this work should open up applications to general energy exchange processes in the solar system and interstellar space, control of ion-molecule exothermic reactions near zero Kelvin, generation of Wigner crystals of molecular ions in a lattice, precision spectroscopy of ions, ultraprecise atomic and molecular ion clocks, and potentially, quantum computers or quantum memory registers involving arrays of trapped ions. The project uses a special hybrid ion-neutral trap (MOT and Paul trap combination) to overlap clouds of alkali-metal atoms and various kinds of ions (e.g. Ca+, Na2+, Na+) and to allow observation of the rates of cooling and reactions that occur as a result. This basic research is relevant to atomic physics, molecular physics, frequency standards, space physics and astrophysics, quantum information and memories and their many applications. Atomic, molecular and optical physics (AMO) research at the University of Connecticut currently involves 10 active faculty and ~38 graduate students who receive a broad education involving all these areas, through their individual research, interaction with peers, weekly research seminars and colloquia, visits from scholars, public lectures and community outreach. Research results are frequently presented at conferences. One of the PI's students in undergraduate quantum mechanics for physics majors is now involved in PhD-level research on this project. Three undergraduate summer students, along with two exchange students from the University of Heidelberg have been involved. Undergraduates are encouraged to participate in related independent study projects. Students on the project receive a broad education in basic experimental physics techniques, including ultrahigh vacuum, laser cooling and trapping, optics, laser spectroscopy, ion manipulation and detection, etc.