Interaction of Ultracold Atoms and Molecules with Surfaces

技术概述：该奖项支持理论物理学领域与超冷原子和分子与表面相互作用相关的研究和教育。该奖项由DMR和NSF EPSCoR合作支持。该研究解决了非摄动描述量子系统动力学的理论挑战，该系统与表面和体激发的连续体强耦合。将非弹性量子散射的多通道公式扩展并应用于量子粘着和解吸。利用耦合积分方程系统的Fredholm理论和图解摄动理论，在低能区寻求渐近解。在开发的多通道形式中，将分析最近在Debye-Waller因子的数值计算中看到的新型多声子共振，并探索非零衬底温度的影响。当粒子能量趋于零时，粘住的概率的行为？量子粘滞的阈值定律？将计算各种模型耦合形式和应用于物理系统的电位，包括：(1)中性原子撞击氦- ii，(2)中性原子撞击简单金属，(3)玻色-爱因斯坦凝聚体（BEC）撞击介电基片，(4)带电原子撞击介电基片，(5)带电原子撞击简单金属。努力将集中在阈值定律偏离量子反射定律的可能性上。研究将包括由多体效应引起的阈值效应(1)最终状态，如红外突变，以及(2)BEC的非线性相互作用。该研究具有很强的教育成分，涉及研究生的培训，并延续了PI长期以来招募本科生参与尖端研究项目并发表成果的历史。非技术概述：该奖项支持与超冷原子和分子与表面相互作用有关的量子物理学的基础理论研究和教育。该奖项由DMR和NSF EPSCoR合作支持。这项研究是基于通常的量子现象，当非常低能量的物体被推进到一个表面并反弹回来时，可以观察到。这与经典系统完全相反，在经典系统中，表面和附近物体之间的吸引力导致它们粘在一起，至少当物体的速度非常小的时候。这种完美量子弹跳现象已经从一种智力好奇心的地位，转变为冷原子研究领域及其与纳米技术相关的核心重要性之一。这一冷原子研究领域的进展对于开发新的小型化原子芯片至关重要，在这种芯片中，原子被困在距离表面不到一微米左右的地方。这项研究将在研究生和本科生的参与下进行，他们将接受现代理论方法与纳米技术应用的培训，为他们在科学和纳米技术领域的职业生涯做好准备。这项研究将与来自美国和国外的科学家合作进行，加强和丰富美国的物理社区。

TECHNICAL SUMMARY:This award supports research and education in theoretical physics in an area related to the interaction of ultracold atoms and molecules with surfaces. The award is supported by DMR and a partnership with NSF EPSCoR. The research addresses the theoretical challenge of non-perturbatively describing the dynamics of a quantum system that is strongly coupled to a continuum of surface and bulk excitations. A multichannel formulation of inelastic quantum scattering will be extended and applied to quantum sticking and desorption. Using Fredholm theory for systems of coupled integral equations and diagrammatic perturbation theory, asymptotic solutions will be sought in the low energy regime. Within the multichannel formalism developed, novel multiphonon resonances recently seen in numerical calculations of the Debye-Waller factor will be analyzed, and the effects of non-zero substrate temperature will be explored. The behavior of the probability of sticking as the particle energy tends to zero?the threshold law for quantum sticking?will be calculated for a variety of model coupling forms and potentials having application to physical systems that include: (1) neutral atoms impinging on helium-II, (2) neutral atoms impinging on simple metals, (3) a Bose-Einstein condensate (BEC) impinging on a dielectric substrate, (4) charged atoms impinging on dielectric substrates, and (5) charged atoms impinging on simple metals. Efforts will focus on the possibility of threshold laws deviating from those ascribed to quantum reflection. Investigations will include threshold effects stemming from many-body effects (1) of the final state such as the infrared catastrophe, and (2) of nonlinear interactions in the case of the BEC.The research has a strong education component involving the training of graduate students and a continuation of the PI's long history of recruiting undergraduates in cutting edge research projects with publishable outcomes.NON-TECHNICAL SUMMARY:This award supports fundamental theoretical research and education on the quantum physics related to the interaction of ultracold atoms and molecules with surfaces. The award is supported by DMR and a partnership with NSF EPSCoR. The research is grounded in the usual quantum phenomena observed when very low energy objects are propelled towards a surface and bounce off. This is exactly the opposite of classical systems where attractions between surfaces and nearby object causes them to stick, at least when the speed of the object is extremely small. This phenomenon of a perfect quantum bounce has moved from the status of an intellectual curiosity to one of central importance in the field of cold atom research and the associated relevance of that to nanotechnology. Advances in this area of cold atom research can be crucial for developing new miniaturized atom chips in which atoms are trapped less than a micron or so from the surface.This research will be conducted with the participation of graduate and undergraduate students who will be trained in modern methods of theory with applications to nanotechnology, preparing them for careers in science and nanotechnology. The research will be performed in collaboration with scientists from the US and abroad, strengthening and enriching the US physical community.