Many-body Rydberg systems

里德堡原子是高度激发的原子，对外场和其他原子都很敏感，因为它们夸张的性质，包括大的极化率和电偶极矩。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，这已被证明导致里德堡激发阻塞。在封闭域中，多个原子共享一个里德堡激发，形成了新颖的量子多体态。在这个项目中，这些多体状态的寿命(消相干)是通过回声类型的实验来探测的，在回声类型的实验中，相干控制技术被用来通过部分或全部逆转系统演化来逆转激发。实现完美回声的程度取决于系统演化的时间反转程度。通过以一种快速、依赖于时间的方式控制原子相互作用，可以测量到回声的完美程度。与完美回波的剩余偏差有望指示运动引起的多体系统的去相干，这是非常重要的基本问题。为了探讨这一主题，我们研究了回声可见性作为样本参数的函数，例如回声序列的温度和持续时间。这个项目正在处理的多体系统进一步展示了里德堡原子位置之间的空间关联。利用空间敏感的离子探测方法对这些关联进行了验证和表征。在相关实验中，研究了原子间激发跃迁的动力学。基于调制驻波激光场的里德堡-里德堡跃迁毫米波光谱新技术的发展提供了进一步的优点。多体里德堡系统的去相干研究具有很高的基础兴趣，并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能会加深对其他复杂量子系统中电子激发动力学的理解，如生物分子、捕光络合物和纳米光子材料。调制有质动势中里德堡原子的光谱可能会对原子性质和基本常数的精确测量产生更广泛的影响。该项目对社会的影响的一个重要部分是对研究生进行研究、口头和书面陈述以及教学方面的培训。因此，研究生为未来在学术界、政府实验室和工业中的责任做好了准备。该项目包括可能适合本科生学习的较小研究部分。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，向普通公众提供服务。这些活动旨在鼓励高中生考虑从事科学或工程工作。

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.