JILA PFC: Bridging theGap from Few-Body to Many-Body through Quantum Control

JILA PFC的主要主题是解决通过量子控制弥合从少体物理到多体物理差距的挑战。核心科学目标是将物理学家对少体系统的控制和理解扩展到多体量子系统。由许多粒子组成的量子系统及其相互作用在许多物理学中起着至关重要的作用，包括凝聚态物理、材料物理、核物理、高能粒子物理、天体物理学、生物物理学和化学物理学。JILA PFC将专注于使用原子、分子和光学（AMO）物理的工具和思想来控制和理解多粒子量子系统的挑战，具有讽刺意味的是，这是一个传统上没有强调多体物理的物理领域。AMO物理学正处于一场革命之中，例如，近年来在超冷气体、超快激光技术和超精密光谱学方面的实验取得了显著成就，就证明了这一点。这一革命提供了一种新的方法来面对复杂的多粒子系统的行为，在量子水平上使用控制。在2011年至2016年期间，JILA PFC研究人员将应用现代AMO物理学的工具来解决从两方面弥合从少体到多体量子物理差距的挑战，使用尖端技术研究超出当前理解的少体问题和超出平均场描述限制的制度中的多粒子系集。需要解决的具体问题是：(1)使用超冷原子和分子气体作为模型系统，可以给量子多体物理带来哪些新的见解？(2)能否扩展AMO的测量和控制技术，利用相干光-物质耦合创建新型多体系统？(3)在从少体到多体的问题中，我们能否通过应用尖端技术来控制和探测简单的分子系统，来理解和解决分子形成的物理学问题，以及更普遍的化学反应问题？(4)与本研究密切相关的潜在高影响力研究方向是什么？这项研究将在JILA进行，JILA是位于博尔德科罗拉多大学校园内的一个多学科研究机构，并以目前PFC资助下取得的广泛成果为基础。在纳米开尔文分子物理学、纳米振荡器和微波场的非经典行为，以及跨越12个数量级的时间尺度的各种固体和液体动力学探针方面的重大成果，都为以下四个主要活动的快速发展奠定了基础：主要活动1：从头开始构建复杂的事物。该领域的工作将探索由超冷原子和分子组装而成的新型量子多体系统中产生的丰富现象。这一重大活动与凝聚态物理有密切联系，将包括对偶极分子量子气体和强相互作用原子量子气体的研究。具体的研究目标包括探索强相互作用粒子气体中气体和液体行为的边界，以及利用超冷极性分子之间的远距离和各向异性相互作用实现量子物质的新状态。主要活动二：利用光-物质耦合的工程量子多体系统。这项活动将通过利用相干光与物质的相互作用，将量子控制扩展到日益复杂的系统。项目将探索冷原子的集体发光，纳米机械振荡器的量子运动，以及材料系统中的光诱导相干性。一个例子是一个雄心勃勃的项目，利用纳米机械“跳水板”作为耦合介质，将微波中的非经典光子态映射到光学模式中的相应态，反之亦然。主要活动3：对抗分子转化。在最基本的层面上，反应是通过电子之间的相互作用和电子与核运动之间的耦合进行的。JILA PFC的研究人员将在这个基础水平上探索反应的物理学，目的是理解和学习控制小系统（如三原子和四原子分子）中的能量流。他们将专注于三个项目：研究冷和超冷反应性分子散射，探测时间分辨核和电子动力学，以及开发相干紫外到红外分子光谱。主要活动四：探索高影响力协同研究方向。JILA中心理念的一个重要方面是，人们应该警惕将有趣的想法和技术“输出”到中心重点以外的活动的机会，并将其引入。JILA将探索其中的一些机会，投资一小部分中心资源来促进这种思想和技术的贸易。主要活动有一个共同的焦点，因此有大量的知识和科学重叠，如果有的话，仍然有更强的技术重叠。先前的经验表明，JILA PFC设想的极具挑战性的目标最好通过流体协作来解决，这些协作可以利用一系列功能，如激光频率梳，超冷原子，先进的VUV源，量子和超快光学，化学物理的敏感检测方法以及计算和分析的理论方法。这种专业知识的多样性不能轻易地在单个调查员的小组中合成。此外，JILA PFC依赖并不断升级共享的技术基础设施，包括世界级的机械车间，以及电子和计算支持，并参与集体教育和推广工作。JILA项目将产生许多不同的更广泛的影响。它将通过开发许多新的基于激光的工具和技术，并通过培养许多不仅在AMO物理方面而且在技术交流和教学技能方面受过高度训练的毕业生，来加强国家的技术基础设施。它将与世界各地的科学界建立联系，并通过组织和举办专题研讨会，通过JILA短期和长期访问计划，以及通过参与JILA合作和跨学科研究的许多本科生，研究生和博士后研究人员，促进领域范围的前沿研究。如上所述，拟议的工作与物理学的许多不同领域有关，包括材料物理学、生物物理学和纳米技术等应用领域。将理解和量子控制从少体系统扩展到多体系统肯定会影响许多应用，如光合作用、催化材料的设计和可再生能源的新技术。该计划还将通过积极的本科研究计划和以少数族裔为主的中学课后充实计划，吸引更多学生进入科学领域，尤其是来自代表性不足群体的学生。它将通过各种各样的项目，包括非常受欢迎的学生“奇才”秀，科罗拉多大学周六物理公开讲座，以及经过适当培训的研究生和博士后研究人员，向科罗拉多州的中学生和高中生介绍科学主题，从而提高公众对科学的兴趣和素养。它还将研究、开发和广泛传播向所有学生教授AMO科学的更好方法，向所有学生教授AMO科学的更好方法，特别是通过在线互动模拟。

The primary theme of the JILA PFC is to address the challenge of bridging the gap from few-body physics to many-body physics through quantum control. The central scientific objective is to extend the remarkable level of control and understanding that physicists have for few-body systems to many-body quantum systems. Quantum systems made up of many particles and their interactions play an essential role in much of physics, including condensed matter physics, material physics, nuclear physics, high-energy particle physics, astrophysics, biophysics, and chemical physics. The JILA PFC will focus upon the challenge of controlling and understanding multi-particle quantum systems using the tools and ideas of atomic, molecular, and optical (AMO) physics, which, ironically, is a field of physics for which many-body physics has not traditionally been emphasized. AMO physics is in the midst of a revolution, evidenced, for example, by the remarkable accomplishments in recent years of experiments on ultracold gases, ultrafast laser technology, and ultraprecise spectroscopy. This revolution affords a new approach for confronting the behavior of complex multi-particle systems using control at the quantum level. In the period 2011- 2016, the JILA PFC investigators will apply the tools of modern AMO physics to tackle the challenge of bridging the gap from few-body to many-body quantum physics from both sides, using cutting-edge techniques to study few-body problems beyond current understanding and many-particle ensembles in regimes beyond the limits of a mean-field description. Specific questions to be addressed are (1) What new insights can one bring to quantum many-body physics using ultracold atom and molecule gases as model systems? (2) Can one extend AMO's measurement and control techniques to create new types of many-body systems using coherent light-matter coupling? (3) Can one understand and address, in the few- to many-body problem, the physics of molecule formation and, more generally, chemical reactions by applying cutting-edge technologies to control and probe simple molecular systems? (4) What are potential high impact research directions that are closely tied to this work? The research will take place at JILA, a multidisciplinary research institute located on the University of Colorado campus in Boulder, and builds upon the extensive results achieved under the present PFC funding. Significant results in nanokelvin molecular physics, in non-classical behavior of nano-oscillators and microwave fields, and in various probes of solid and liquid dynamics across timescales that span twelve orders of magnitude, all set the stage for rapid future progress in four major activities:.Major Activity 1: Building complex matter from the ground up.Work in this area will explore the rich phenomena arising in novel quantum many-body systems that are assembled from ultracold atoms and molecules. This major activity, which has strong connections to condensed matter physics, will include research in dipolar molecular quantum gases and strongly interacting atomic quantum gases. Specific research goals include exploring the boundary between gaseous and liquid behavior in gases of strongly interacting particles, and realizing novel states of quantum matter using the long-range and anisotropic interactions between ultracold polar molecules.Major Activity 2: Engineering quantum many-body systems using light-matter coupling.This activity will extend quantum control to increasingly complex systems by exploiting coherent light matter interactions. Projects will explore collective light emission from cold atoms, the quantum motion of nano-mechanical oscillators, and light-induced coherence in material systems. An example project is an ambitious effort to map non-classical photon states in the microwave onto corresponding states in optical modes and vice versa, using a nanomechanical "diving board" as the coupling medium.Major Activity 3: Confronting molecular transformation.At the most basic level, reactions proceed via the interaction between electrons and the coupling between electronic and nuclear motion. JILA PFC investigators will explore the physics of reactions at this fundamental level, with the goal of understanding, and learning to control, energy flow in small systems such as triatomic and tetratomic molecules. They will focus on three projects: studying cold and ultracold reactive molecular scattering, probing time-resolved nuclear and electronic dynamics, and developing coherent UV to IR molecular spectroscopy.Major Activity 4: Exploring high impact synergistic research directions.An essential aspect of JILA's center philosophy is that one should be alert to opportunities to "export" interesting ideas and technologies to activities outside the central focus of the center, and to import these as well. JILA will explore a few of these opportunities, investing a small fraction of center resources in facilitating this trade in ideas and technology.The major activities share a common focus, and therefore have substantial intellectual and scientific overlap, and, if, anything, still stronger technological overlap. Prior experience has shown that the extraordinarily challenging goals envisioned for the JILA PFC are best tackled with fluid collaborations that can draw on a range of capabilities, such as laser frequency combs, ultracold atoms, advanced VUV sources, quantum and ultrafast optics, the sensitive detection methods of chemical physics, and theoretical methods, both computational and analytic. This diversity of expertise cannot readily be synthesized in an individual investigator's group. In addition, the JILA PFC relies on and continuously upgrades a shared technical infrastructure including a world-class machine shop, as well as electronics and computational support, and engages in a collective program of education and outreach efforts.The JILA program will have many different broader impacts. It will enhance the nation's technical infrastructure by developing many new laser-based tools and techniques, and by producing many graduates who are highly trained not only in AMO physics but also in technical communication and teaching skills. It will connect with the science community around the world and foster field-wide frontier research through organization and hosting of topical workshops, through a short-term and long-term JILA visitor program, as well as through the many undergraduate students, graduate students, and postdoctoral researchers who participate in the collaborative and interdisciplinary research at JILA. As discussed above, the proposed work connects to many different areas of physics, including applied areas such as materials physics, biophysics, and nanotechnology. Extending understanding and quantum control from few- to many-body systems will certainly impact many applications, such as photosynthesis, design of catalytic materials, and new techniques in renewable energy. The proposed program will also attract more students into science, particularly from under-represented groups, through a vigorous undergraduate research program and a predominantly minority-serving middle-school after-school enrichment program. It will contribute to general science interest and literacy through a variety of programs that include the very popular "Wizards" show for school children, the University of Colorado Saturday Physics public talks, and suitably trained graduate students and postdoctoral researchers who present science topics to Colorado middle-school and high-school students. It will also research, develop, and broadly disseminate better ways to teach AMO science to all students, better ways to teach AMO science to all students, particularly through on-line interactive simulation.