Many-body Rydberg systems

里德伯原子是高度激发的原子，由于其夸张的性质，包括大的极化率和电偶极矩，对外部场和其他原子敏感。在激光冷却的原子样品中，这些性质导致了强烈的里德堡-里德堡相互作用，这种相互作用已被证明会导致里德堡激发封锁。在封闭域中，一个里德伯激发在许多原子之间共享，导致新的量子多体态。在这个项目中，使用回声型实验来探测这些多体态的寿命（退相干），其中相干控制技术通过系统演化的部分或全部时间逆转来逆转激励。达到完美回声的程度取决于系统演化的时间逆转能力。通过以一种快速的、随时间变化的方式控制原子相互作用，可以测量出多么完美的回波。完美回波的残余偏差被认为是运动引起的多体系统去相干的指示，这是一个非常重要的基础问题。为了探讨这一问题，研究了回波可见性作为温度和回波序列持续时间等样本参数的函数。这个项目正在处理的多体系统进一步展示了里德伯原子位置之间的空间相关性。这些相关性被证明和表征使用空间敏感离子检测方法。在相关实验中，研究了原子间的激发跳变动力学。进一步的优点是基于调制驻波激光场的Rydberg-Rydberg跃迁的毫米波光谱的基本新技术的发展。多体里德伯系统的脱相干研究具有重要的基础意义，在量子信息处理中具有重要意义。多体Rydberg系统中量子输运的研究可以进一步理解其他复杂量子系统中电子激发的动力学，如生物分子、光收集配合物和纳米光子材料。调制质动势中的里德伯原子光谱学可以对原子性质和基本常数的精确测量产生广泛的影响。该项目对社会影响的一个重要部分是培养研究生的研究、口头和书面报告以及教学。因此，研究生为将来在学术界、政府实验室和工业界的工作做好了准备。该项目包括较小的研究组成部分，可能适合本科生的工作。通过参与密歇根大学物理奥林匹克竞赛、密歇根数学和科学学者计划以及科学咖啡馆讲座，PI向公众提供了外展服务。这些活动旨在鼓励高中生考虑从事科学或工程方面的职业。

Rydberg atoms are highly excited atoms that are sensitive to external fields and other atoms due to their exaggerated properties, which include large polarizabilities and electric-dipole moments. In laser-cooled atom samples, these properties result in strong Rydberg-Rydberg interactions that have been shown to cause a Rydberg excitation blockade. In the blockaded domain, one Rydberg excitation is shared among many atoms, leading to novel quantum many-body states. In this project, the lifetime (decoherence) of these many-body states is probed using echo-type experiments, in which coherent-control techniques are used to reverse excitations via partial or full time reversal of the system evolution. The degree to which a perfect echo can be achieved depends on how well the system evolution can be time-reversed. It is measured how perfect an echo can be achieved by controlling the atomic interactions in a fast, time-dependent manner. Residual deviations from a perfect echo are expected to be indicative of motion-induced de-coherence of the many-body system, which is of high fundamental interest. To explore this topic, the echo visibility is studied as a function of sample parameters such as temperature and duration of the echo sequence. The many-body system this project is dealing with further exhibits spatial correlations between the locations of the Rydberg atoms. These correlations are demonstrated and characterized using a spatially sensitive ion detection method. In related experiments, the dynamics of excitation hopping between atoms is studied. Further merit is provided by the development of a fundamentally new technique for millimeter-wave spectroscopy of Rydberg-Rydberg transitions, based on modulated standing-wave laser fields.The research on de-coherence of many-body Rydberg systems is of high fundamental interest and has implications in quantum information processing. The study of quantum transport in many-body Rydberg systems may further the understanding of the dynamics of electronic excitations in other complex quantum systems, such as biological molecules, light harvesting complexes and nanophotonic materials. Spectroscopy of Rydberg atoms in modulated ponderomotive potentials could have a broader impact on precision measurement of atomic properties and fundamental constants. An important part of the project's impact on society is the training of graduate students in research, oral and written presentation, and teaching. The graduate students are thereby prepared for future responsibilities in academia, government laboratories, and industry. The project includes smaller research components that may be suitable for undergraduate work. Outreach to the general public is provided through the PI's involvement in the University of Michigan Physics Olympiad, the Michigan Math and Science Scholars program, and Science Cafe talks. These activities aim at the encouragement of high-school students to consider a career in science or engineering.