Studies Involving Atoms in High Rydberg States

在这个项目中，处于精心设计的状态的原子具有相当大的内部能量，称为激发态，用于研究原子如何相互作用以及这种相互作用的结果。例如，原子-原子相互作用位于许多提出用于量子信息处理的协议的核心，并提供了一种新的方法来探测磁性和超导等现象。激光束被用来产生受激发的原子态，其物理特征以及相互作用，然后使用一系列精心定制的脉冲电场来操纵。使用这种“设计者原子”能够更详细地探索原子与原子的相互作用，并能够创造新的化学键和新的分子物种。激光产生的原子很大，位于以量子理论为特征的微观世界和由牛顿定律支配的更大的经典世界之间的交界处。这项工作在这两个领域之间提供了一座桥梁，并有助于阐明从量子到经典行为的转变。高n里德堡态的原子被用来研究强耦合里德堡系统，产生长寿命的两电子激发的“行星原子”，并探索由里德堡原子组成的超长程里德堡分子的物理和化学性质，里德堡原子的电子云嵌入了一个或多个弱束缚基态原子。这项工作涉及用多光子激光激发在热原子束和超冷原子云中产生的高n，n~200-400锶里德堡原子。强相互作用的里德堡系统是通过利用偶极阻塞和聚焦的激光来创建两个或更多具有明确初始分离的里德堡原子而创建的。然后，通过使用先前开发的利用脉冲电场设计高n态的协议，通过激发它们到更高的状态来增强它们的相互作用。研究了产物强耦合系统的时间演化，以探索能量交换和寻找长寿命组态，在这些组态中，由于它们的关联运动，激发的电子保持很远的距离。行星原子是通过首先将里德堡电子放置在近圆形轨道上，然后将第二个内价电子激发到高位状态而产生的。里德堡分子的形成是通过它们的激发光谱的位移来确定的。这样的转变也说明了它们的结构和性质。目前的研究承诺对强相互作用的少体系统的行为有新的见解，这些行为构成了许多提出用于量子信息处理的协议的基础，并由此扩展到多体系统的行为，在这些多体系统中，相互作用引起了凝聚态物理的各种基本现象。这项工作还提供了关于超快超强区域的物理信息，并涉及使用阿秒激光脉冲设计低位原子态。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

In this project atoms in carefully engineered states that possess sizable internal energy, termed excited states, are used to study how atoms interact with one another together with the outcomes of such interactions. Atom-atom interactions, for example, lie at the very heart of many of the protocols proposed for quantum information processing and provide a novel means to probe phenomena such as magnetism and superconductivity. Laser beams are used to create excited atomic states whose physical characteristics, and hence interactions, are then manipulated using a carefully tailored series of pulsed electric fields. Use of such "designer atoms" enables atom-atom interactions to be probed in great detail and allows creation of novel chemical bonds and new molecular species. The laser-created atoms are large and lie at the interface between the microscopic word, characterized by quantum theory, and the larger classical world governed by Newton's Laws. This work provides a bridge between these two realms and helps illuminate the transition from quantum to classical behavior.Atoms in high-n Rydberg states are used to study strongly-coupled Rydberg systems, to generate long-lived two-electron-excited "planetary atoms," and to explore the physical and chemical properties of ultralong-range Rydberg molecules which comprise a Rydberg atom in whose electron cloud are embedded one, or more, weakly-bound ground state atoms. The work involves high-n, n~200-400, strontium Rydberg atoms created in both hot atomic beams and in ultracold atom clouds using multiphoton laser excitation. Strongly interacting Rydberg systems are created by exploiting dipole blockade and focused laser beams to create two, or more, Rydberg atoms with well-defined initial separations. Their mutual interactions are then increased by exciting them to higher-lying states using protocols developed previously to engineer high-n states with pulsed electric fields. The time evolution of the product strongly coupled system is examined to explore energy interchange and to search for long-lived configurations where, due to their correlated motions, the excited electrons remain far apart. Planetary atoms are created by first placing the Rydberg electron in a near-circular orbit and then exciting the second inner valence electron to a high-lying state. Rydberg molecule formation is identified spectroscopically through shifts in their excitation spectra. Such shifts also illuminate their structure and properties. The present studies promise new insights into the behavior of strongly interacting few-body systems which form the basis for many protocols proposed for quantum information processing and, by extension, into the behavior of many-body systems where interactions give rise to a wide variety of phenomena fundamental to condensed matter physics. The work also furnishes information on physics in the ultra-fast ultra-intense regime and speaks to the engineering of low-lying atomic states using attosecond laser pulses.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.