Observation and Control of Coherent Processes Involving Rydberg Atoms

这个项目将研究单个原子对外部刺激的基本反应，比如其他原子的存在或非常短的明亮激光脉冲。实验将使用“里德伯原子”（其中至少有一个带负电荷的电子比正常情况下拥有更多的能量，并且围绕带正电荷的原子核在一个大而缓慢的轨道上运动）。因为在里德伯原子中，原子核和远处电子之间的电作用力非常弱，所以它们对周围环境非常敏感。这种灵敏度将在实验中得到利用，放大原子对环境的反应，使其更容易改变电子的运动或以可控的方式操纵原子之间的力。其中一些实验可能直接应用于量子计算，因为里德伯原子可能用于存储和处理信息。在其他情况下，实验将为涉及更复杂系统的问题提供见解，例如光收集系统中的能量转移，或者使用非常短的激光脉冲在极短的时间间隔内观察分子中的电子运动（所谓的“阿秒”政权，比1秒小一百万万亿倍）。实验将利用超快和冷原子技术，单独或结合，利用强烈的超短太赫兹脉冲和受控的原子间耦合来操纵电子动力学和/或原子-原子相关性。这些系统在超快/强场物理和冷原子物理的界面上为探索少体和多体量子力学的新方面提供了丰富的机会。要解决的问题代表着真正的挑战，因为与动力学相关的空间和时间尺度跨越了许多数量级，从单个原子内的电子运动到涉及多个原子的相关性。一组实验将寻求进一步表征暴露在强烈的、真正的单周期脉冲下的原子的新型电离行为。另一种将尝试使用这种脉冲来诱导电离和重组，相干地将束缚电子从原子传递到相邻原子。第三条实验线将利用有效的激光激发原子对在规定的原子间距离内进入和退出里德伯态，切换原子之间的强排斥相互作用，以操纵磁光阱中冷原子的位置相关性。在没有明确的外部约束势的情况下产生自有序原子阵列的可能性将被研究。最后，原子之间受控的偶极-偶极耦合将被用来纠缠相邻原子上的电子波包，导致相干电子波包运动从原子转移到它们的邻居，距离为几微米。从提出的实验中获得的新见解有可能影响其他几个科学领域，包括凝聚态物理、化学物理、量子信息、量子控制和阿秒科学。

This project will study the fundamental response of individual atoms to external stimuli, such as the presence of other atoms or very brief pulses of bright laser light. The experiments will use "Rydberg atoms" (those in which at least one of the negatively-charged electrons has much more energy than normal and moves in a large, slow orbit around the positively-charged nucleus). Because the electric forces between the nucleus and the distant electron are so weak in Rydberg atoms, they are very sensitive to their surroundings. This sensitivity will be exploited in the experiments, magnifying the atom's response to its environment and making it easier to change the electron's motion or manipulate the forces between atoms in controlled ways. Some of the experiments could have direct applications in quantum computing because Rydberg atoms might serve to store and process information. In other cases, the experiments will provide insights to problems involving more complex systems, for example energy transfer in light harvesting systems, or the use of very brief laser pulses to view electron motion in molecules over extremely short time intervals (the so-called "attosecond" regime, which is a million-trillion times smaller than 1 second).The experiments will utilize ultrafast and cold atom techniques, separately and in combination, exploiting intense ultrashort terahertz pulses and controlled interatomic couplings to manipulate electron dynamics and/or atom-atom correlations. These systems are rich with opportunities for exploring novel aspects of few- and many-body quantum mechanics at the interface between ultrafast/strong field physics and cold atom physics. The problems to be addressed represent real challenges as the spatial and temporal scales relevant to the dynamics span many orders of magnitude, from electronic motion within individual atoms to correlations involving multiple atoms. One set of experiments will seek to further characterize the novel ionization behavior of atoms exposed to intense, true single-cycle pulses. Another will attempt to use such pulses to induce both ionization and recombination, coherently shuttling bound electrons from atoms to their neighbors. A third line of experiments will utilize efficient laser excitation of atom pairs into, and out of, Rydberg states at prescribed interatomic distances, toggling strong repulsive interactions between atoms to manipulate the position correlation of cold atoms in a magneto optical trap. Possibilities for producing self-ordered arrays of atoms without an explicit external confinement potential will be pursued. Lastly, controlled dipole-dipole couplings between atoms will be used to entangle electronic wavepackets on neighboring atoms, resulting in the transfer of coherent electronic wavepacket motion from atoms to their neighbors, at distances of several microns. New insights obtained from the proposed experiments have the potential to impact several other scientific areas including condensed matter physics, chemical physics, quantum information, quantum control, and attosecond science.