Control of Ultracold Dynamics and Decoherence Using Optical Frequency Combs

智力价值：该项目致力于光学频率梳与超冷原子和分子系统相互作用的理论研究。它的目标是发展量子控制方法来操纵超冷气体中的动力学，创造和控制超冷分子并减轻随之而来的退相干。本文将建立一个考虑到弛豫Liouville - von Neumann方程框架内的衰减和碰撞减相的超快锁相脉冲串与多能级系统相互作用的半经典理论。目的是了解涉及双光子拉曼跃迁的超冷温度下光-物质相互作用的机制，并在制备所需的叠加态和控制超冷动力学（例如振动阶梯攀登）中实现它们。新开发的方法将包含减轻或防止系统退相干的元素。重点将放在极性分子，如KRb分子和原子系统，如铷-85和铷-87的研究上。振幅和相位调制将应用于形成光频率梳的脉冲串。将进行盛装态分析，以揭示调制梳与超冷原子和分子相互作用的机制，并深入了解动力学的量子控制，包括系统中存在退相干的情况。这些研究的完成将推进关于超冷温度下光-物质相互作用的知识，并将提供新的量子控制方法，这些方法对实验实现具有鲁棒性。更广泛的影响：新开发的超冷控制方法有望推进和拓宽应用领域，从超冷化学反应到量子信息和量子计算，再到计量学。研究生将通过开发理论模型、编程、收集和解释数值计算数据来参与拟议的调查。关于光学频率梳应用的新发现将被纳入PI每两年开发和教授的研究生课程“量子控制方法”的材料中。在本课程中，学生将了解基于激光技术最新发展的先进量子控制方法。所有这些都为他们的职业发展拓宽了机会。将与史蒂文斯理工学院和其他大学的实验小组合作，旨在在实验研究中实施新开发的控制方法。

Intellectual Merit: The project is devoted to theoretical investigations of the optical frequency comb's interaction with ultracold atomic and molecular systems. It is aiming at the development of quantum control methods to manipulate dynamics in ultracold gases, to create and control ultracold molecules and mitigate the attendant decoherence. A semiclassical theory of ultrafast, phase-locked pulse train interaction with multilevel systems will be developed, taking into account the decay and collisional dephasing in the framework of the Liouville von Neumann equations with relaxation. The objective is to understand the mechanisms of light-matter interaction at ultracold temperatures that involve two-photon Raman transitions, and to implement them in preparing desired superposition states and controlling ultracold dynamics, e.g., vibrational ladder climbing. The newly developed methods will contain elements that mitigate or prevent decoherence in the system. The focus will be on the studies of polar molecules, such as the KRb molecule, and atomic systems, e.g.,Rubidium-85 and Rubidium-87. The amplitude and phase modulation will be applied to the pulse trains that form optical frequency combs. Dressed state analysis will be performed to uncover the mechanisms of modulated combs' interaction with ultracold atoms and molecules, and to gain insights on quantum control of the dynamics, including the case when decoherence is present in the system. The completion of these investigations will advance knowledge about light-matter interactions at ultracold temperatures and will provide new methods of quantum control that are robust for experimental realization.Broader Impact: Newly developed ultracold control methods are expected to advance and broaden fields of applications, from ultracold chemical reactions, to quantum information and quantum computation, to metrology. Graduate students will get involved in the proposed investigations through developing theoretical models, programming, collecting and interpreting data of numerical calculations. New findings on applications of optical frequency combs will be incorporated into the material of the graduate course "Methods of Quantum Control" which the PI has developed and teaches every other year. Within this course, students learn about the advanced quantum control methods based on the latest developments of laser technologies. All of this broadens opportunities for their career development. Collaboration with experimental groups at Stevens Institute of Technology and other universities will be initiated, aiming at implementing newly developed control methods in experimental investigations.