Interaction of Ultracold Atoms and Molecules with Surfaces

技术综述：该奖项支持与超冷原子和分子与表面相互作用相关领域的理论物理研究和教育。该奖项由DMR支持，并与NSF EPSCoR合作。这项研究解决了以非微扰方式描述与表面和体激发的连续体强耦合的量子系统的动力学的理论挑战。非弹性量子散射的多通道公式将被推广并应用于量子粘着和解吸。利用耦合积分方程组的Fredholm理论和图解摄动理论，在低能区可求出渐近解。在发展的多通道形式下，将分析最近在德拜-沃勒因子的数值计算中看到的新的多声子共振，并将探索非零衬底温度的影响。当粒子能量趋于零时，粘着概率的行为(量子粘着的阈值定律)将针对适用于物理系统的各种模型耦合形式和势进行计算，这些耦合形式和势包括：(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)撞击介质衬底，(4)带电原子撞击介质衬底，以及(5)带电原子撞击简单金属。努力将重点放在阈值定律偏离那些归因于量子反射的可能性上。研究将包括来自多体效应的阈值效应(1)终态，如红外灾难，以及(2)在BEC的情况下的非线性相互作用。这项研究具有强大的教育成分，涉及研究生的培训，并延续了PI在具有可发表结果的尖端研究项目中招募本科生的长期历史。非技术总结：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的基础理论研究和教育。该奖项由DMR支持，并与NSF EPSCoR合作。这项研究是基于非常低能量的物体被推向表面并反弹时观察到的常见量子现象。这与经典系统正好相反，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，至少在物体速度极小的情况下是这样。这种完美的量子反弹现象已经从智力上的好奇心转变为冷原子研究领域的核心重要性之一，以及与纳米技术相关的问题。冷原子研究领域的进展对于开发新的微型原子芯片至关重要，在这种芯片中，原子被捕获到表面不到一微米的地方。这项研究将由研究生和本科生参与，他们将接受现代理论方法的培训，并应用于纳米技术，为他们在科学和纳米技术领域的职业生涯做准备。这项研究将与来自美国和国外的科学家合作进行，以加强和丰富美国物理界。

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.