Rydberg-Atom Physics in Ponderomotive Traps and Atomic Imaging Devices

在“重动力阱和原子成像器件中的里德伯原子物理”项目中，对里德伯原子的光晶格偶极子阱进行了开发、改进和应用研究。这些光学陷阱具有陷阱诱导的能级位移，比静态场陷阱小得多。因此，它们非常适合高精度光谱和量子信息处理应用，这些应用目前备受关注。这些晶格表现出丰富多样的绝热俘获势，并通过激光光谱进行了研究。测量了晶格诱导光电离对捕获里德伯原子的影响。提出了一种基于微波调制光晶格光束的光谱学方法。该方法使研究小组能够在不使用大场的情况下驱动高阶多极跃迁，而大场会导致电平偏移，并且具有高空间分辨率。研究小组开发了用于光捕获圆态里德伯原子微波光谱的三维光学晶格。这项工作有望对里德伯常数进行高精度测量。在第二部分的工作中，一个尖端成像探针（tip）被用来执行多体里德伯系统的相关性的空间域测量。在这些系统中，几个去局域的里德伯激发在高度纠缠的量子态的大量冷原子之间相干共享。TIP系统通过离子成像读出样品中单个里德堡激发的位置。使用TIP装置进行的新测量使研究人员能够在测量信号中分离出由阻塞引起的效应和由于库仑离子排斥引起的效应。TIP实验用于在随机分布的基态原子样品中制备和检测由绝热通道激发的里德伯原子晶体。捕获单个原子仍然是原子、分子和光学物理学的一个主要主题。在所谓的“光学晶格”中，几个相交的激光束被用来形成一个周期性的陷阱点网格来陷阱原子。光学晶格很像一个鸡蛋盒，在周期性的位置放置鸡蛋（鸡蛋是原子的类似物）。在这个项目中，密歇根的一个研究小组为里德伯原子开发了这样的光学晶格。里德伯原子是一种巨大的原子，它有一个束缚非常松散的电子，平均来说，这个电子在离原子中心很远的地方运动。研究界认为，从长远来看，激光陷阱中的里德伯原子可以帮助开发强大的量子计算机，它可以处理普通计算机无法解决的数学问题。密歇根大学团队开发的光学里德伯原子陷阱也有可能获得基本常数的信息，比如里德伯常数。对这些常数的测量具有很大的价值，因为它们可以检验我们目前对物质组成和自然内部运作的理解。在这个项目中，研究生和本科生接受研究、研究报告和同伴指导方面的培训。整个项目对社会产生了更广泛的影响，因为各级学生都准备好承担科学、工业和教育领域的重要任务。该项目还附带了一些旨在鼓励高中生考虑从事科学或工程职业的拓展部分，比如密歇根物理奥林匹克竞赛。

In the project entitled "Rydberg-atom physics in ponderomotive traps and atomic imaging devices" optical-lattice dipole traps for Rydberg atoms are developed, improved and applied in research. These optical traps have trap-induced level shifts that are much smaller than those in static-field traps. They are therefore well suited for high-precision spectroscopy and quantum information processing applications that are currently of high interest. The lattices exhibit a rich variety of adiabatic trapping potentials, which are studied via laser spectroscopy. The effect of lattice-induced photo-ionization on the trapped Rydberg atoms is measured. A spectroscopic method is developed that is based on microwave modulation of the optical-lattice beams. The method allows the research team to drive high-order multipole transitions without the application of large fields, which would cause level shifts, and with high spatial resolution. The research team develops three-dimensional optical lattices for microwave spectroscopy of optically trapped circular-state Rydberg atoms. The work has the prospect of yielding a high-precision measurement of the Rydberg constant.In the second component of the work, a tip imaging probe (TIP) is employed to perform spatial-domain measurements of correlations in many-body Rydberg systems. In these systems, several de-localized Rydberg excitations are coherently shared between a large number of cold atoms in a highly entangled quantum state. The TIP system reads out the positions of individual Rydberg excitations in the sample via ion imaging. New measurements with the TIP setup allow the researchers to separate blockade-induced effects and effects due to Coulomb ion repulsion in the measured signals. The TIP experiment is applied to prepare and detect Rydberg atom crystals excited by adiabatic passage in randomly distributed samples of ground-state atoms.Trapping individual atoms continues to be a major theme in atomic, molecular and optical physics. In a so-called "optical lattice," several intersecting laser beams are used to form a periodic grid of trap sites to trap atoms. An optical lattice is much like an egg carton holding eggs at periodic locations (where an egg is the atom's analogue). In this project a Michigan research team develops such optical lattices for Rydberg atoms. A Rydberg atom is a giant atom with one very loosely bound electron that travels, on average, quite far away from the atom's center. The research community believes that, in the long term, Rydberg atoms in laser traps can be helpful in the development of powerful quantum computers, which can treat mathematical problems that ordinary computers cannot solve. The optical Rydberg atom traps the Michigan team develops also have the potential of yielding information on fundamental constants, such as the Rydberg constant. Measurements of such constants are of great value because they serve as tests of our current understanding of the composition of matter and the inner workings of nature. In the project, graduate and undergraduate students are trained in research, research presentation, and in peer instruction. The project as a whole has a broader impact on society in that students at all levels become prepared to assume important tasks in science, industry and education. The project is accompanied by outreach components that aim to encourage high-school students to consider careers in science or engineering, such as the Michigan Physics Olympiad.