Rydberg Atom Interactions and Collective Behavior

里德伯原子的极大极化率导致在微米的核间距离上的相互作用大于它们在超冷温度（T小于1毫开尔文）下的动能。远距离相互作用使超冷里德伯原子成为研究偶极量子气体、构建单光子源和构建量子门的重要系统。它们对电场的敏感性使里德伯原子在传感和测量标准中的应用非常有用。利用里德伯原子偶极子封锁产生量子纠缠物质粒子的能力，增加光物质相互作用次数，并创造奇异态，如大二聚体和三叶虫分子，进一步推动了超冷里德伯原子的研究。我们正在解决的关键问题是：如何控制相互作用的各向异性，静态背景电场的作用是什么，超冷气体中的里德伯原子-电子散射如何导致物质有趣状态的形成，以及当两个里德伯原子在短距离相互作用时会发生什么？利用独特的碰撞成像光谱仪对超冷基态原子与里德伯原子电子之间的相互作用进行了实验研究。由于基态原子的弱束缚里德伯电子散射，预测会发生相变和磁现象，目前正在研究中。这些实验补充了其他关于里德伯原子-里德伯原子相互作用的实验，这些实验定量地测量了相互作用的各向异性及其对假设发生在超冷里德伯气体中的相变的影响。这些实验的结果正在与我们研究小组所做的理论进行比较。该奖项支持两名研究生，并使本科生的研究项目能够在该设备上进行。

The extremely large polarizability of Rydberg atoms leads to interactions at internuclear distances of microns that are larger than their kinetic energies at ultracold temperatures (T less than 1 milliKelvin). The long range interactions make ultracold Rydberg atoms important systems for studying dipolar quantum gases, building single photon sources and constructing quantum gates. Their sensitivity to electric fields makes Rydberg atoms useful for applications in sensing and measurement standards. The ability to generate quantum entangled material particles using Rydberg atom dipole blockade, increase light matter interaction times, and create exotic states, like macrodimers and trilobite molecules, has further motivated the study of ultracold Rydberg atoms. Key questions that we are addressing are: how can the anisotropy of the interactions be controlled, what is the role of static background electric fields, how does Rydberg atom-electron scattering in ultracold gases lead to the formation of interesting states of matter and what happens when two Rydberg atoms interact at short range? Specifically, the interaction between ultracold ground state atoms and Rydberg atom electrons is being investigated experimentally with a unique collision imaging spectrometer. Phase transitions and magnetic phenomena that are predicted to occur due to the scattering of the weakly bound Rydberg electron from the ground state atoms are being studied. These experiments complement others on Rydberg atom- Rydberg atom interactions, which quantitatively measure the anisotropy of the interactions and their influence on phase transitions that are postulated to occur in ultracold Rydberg gases. The results of these experiments are being compared to theory done by our research group. This award supports two graduate students and enables undergraduate research projects to be carried out on the apparatus.