Spectroscopy of Rydberg Atoms in Optical Lattices and Laser Traps

密歇根大学的物理学家正在使用“有质动力光谱学”，这是一种先进的技术形式，至少可以追溯到17世纪，当时艾萨克·牛顿第一次证明了白光通过棱镜射入彩虹。新的高分辨率光谱学使研究人员能够更深入地观察原子的结构，并在更精细的尺度上指导它们的行为。因此，由有质动力光谱学实现的测量可能会导致基础物理学的进步，并促进科学的进步。在他们的研究中，科学家们使用了里德堡原子--这种巨大的原子不仅比通常的原子更大，而且相互作用也更强。里德堡原子使有质动力光谱学的新方法成为可能。此外，它们还允许探测微小的电磁场，这可能会提高我们测量自然或人类活动的能力，以及研究量子力学物质(行为类似波的物质)系统如何相互作用。详细地说，研究人员使用了一种光谱方法，在调制的光学晶格激光陷阱中制备高激发的里德堡原子。激光冷却的基态原子在光学晶格中被激发到里德堡能级。晶格场通过有质运动的光-电子相互作用保持着微妙束缚的里德堡电子，这反过来又导致对整个原子的捕获力。然后，依赖于时间的微波调制陷阱场驱动里德堡原子能级之间的跃迁，里德堡原子能级的能量被调制频率的奇次谐波分开。探讨了晶格调制光谱的频率分辨率和精度极限。该方法被用来测量原子量，如量子缺陷、离子极化率和里德堡常数。利用腔产生的里德堡原子晶格的非常深的实现，测量了强混合里德堡绝热态的能量。其他测量目标是低原子能级的极化率和光在腔产生的光学晶格中密集填充的冷原子通道中的传播。在第二个研究部分，使用基于里德堡原子场电离、离子提取和空间成像的直接原子成像技术测量里德堡原子对的轨迹。轨迹测量揭示了原子间作用力及其各向异性。里德堡原子与原子的相互作用是通过里德堡原子斯塔克图中Landau-Zener交叉点的绝热通道来控制的，这使得可以制备致密的、高度偶极的量子物质。

Physicists at the University of Michigan are useing "ponderomotive spectroscopy," an advanced form of a technique that traces back at least to the 17th century when Isaac Newton first showed that white light sent through a prism breaks into a rainbow. The new high-resolution spectroscopy allows the researchers to peer more deeply into the structure of atoms and direct their behavior at a much finer scale. The measurements made possible by ponderomotive spectroscopy could thus lead to advances in fundamental physics and promote the progress of science. In their research, the scientists use Rydberg atoms--giant atoms that exhibit not only greater size, but also stronger interactions than usual atoms. Rydberg atoms enable the new method of ponderomotive spectroscopy. In addition, they allow for the detection of small electromagnetic fields, which may improve our ability to measure natural or human activity, as well as investigate how systems of quantum-mechanical matter (matter that behaves like waves) interact with each other.In detail, the researchers employ a spectroscopic method in which highly excited Rydberg atoms are prepared in a modulated optical-lattice laser trap. Laser-cooled ground-state atoms are excited into Rydberg levels within the optical lattice. The lattice field holds on to the tenuously bound Rydberg electron via the ponderomotive light-electron interaction, which in turn results in a trapping force for the entire atom. Time-dependent microwave modulation of the trapping field then drives transitions between Rydberg-atom levels whose energies are separated by odd harmonics of the modulation frequency. The frequency-resolution and accuracy limits of lattice modulation spectroscopy are explored. The method is employed to measure atomic quantities, such as quantum defects, ionic polarizabilities and the Rydberg constant. Using a cavity-generated, very deep implementation of the Rydberg-atom lattice, the energies of strongly mixed Rydberg adiabatic states are measured. Other measurement objectives are the polarizabilities of low-lying atomic levels and light propagation in the densely filled cold-atom channels present in the cavity-generated optical lattice. In a second research component, the trajectories of Rydberg-atom pairs are measured using a direct atom imaging technique, which is based on Rydberg-atom field ionization, ion extraction and spatial imaging. The trajectory measurements reveal interatomic forces and their anisotropy. The Rydberg-atom interactions are controlled via adiabatic passage in Landau-Zener crossings in the Rydberg-atom Stark map, which allows the preparation of dense, highly dipolar quantum matter.