Quantum materials and quantum sensors with atomic and molecular gases

量子力学是我们用来描述和预测物理系统行为的通用数学语言。 量子力学的预言虽然包含标准或所谓的“经典”性质，但也包括奇异和令人惊讶的现象，这些现象既挑战了我们对现实本质的看法，又通过更好的通信（量子密码学）、数据存储（固态设备中的量子效应）、惯性导航（原子干涉仪）和测量技术（量子传感器）被利用来改善社会。该研究计划的目的是利用激光冷却气体探索多体量子现象中的基本问题，并利用这些气体实现具有工业和商业相关性的新量子传感器。激光冷却原子和分子的技术突破开创了超低温科学的新领域。 在非常接近绝对零度的温度下（在微米到纳米开尔文范围内），这些超冷量子材料为我们提供了通过任何其他方式无法获得的全新传感元件和新的物质状态。 这些系统中独特的检测方法和控制程度（包括动态调整粒子-粒子相互作用，粒子密度和限制几何的能力），为少数和多体量子力学中一些最重要和最基本的现象提供了直接的实验途径。 例如，考虑这样一个问题：“强相互作用量子粒子系统的集体行为是什么？这个问题对于理解从微观到天文尺度的一系列基本和技术感兴趣的物理系统至关重要，包括夸克-胶子等离子体，高温超导体中的电子，超流体液氦，超冷原子气体和中子星中的核子。 事实上，除了基本粒子之外，所有存在的物理对象都是一个多体量子系统，而目前对强相互作用多体系统的理论理解仍然有限，因为相互作用可以使粒子-粒子关联支配行为，而平均场理论和微扰分析是不够的。为了推进基础知识和技术，必须通过将新的理论方法与干净和可重复的实验测量进行比较来确定其有效性。 超冷原子或分子气体已经证明它们是用于此目的的理想实验测试平台，因为它们具有上述的控制程度，它们的可重复性以及它们产生的广泛的测量选项。 除了研究量子材料，我们的目标是创建新的传感器，其中传感器元件本身是物质的量子（例如单个原子或单个分子）。 冷原子已经被用来实现最精确和灵敏的重力和惯性传感器与物质波干涉测量，并实现我们的主要频率/时间标准（原子喷泉钟）。 我们将开始与我们最近展示的一种新的传感器技术的发展-使用冷原子来测量超高真空中的粒子通量。 这项技术预计将影响，除其他事项外，半导体制造工艺，依赖于控制粒子密度和真空中的通量。 通过这些方式，对冷原子和分子气体的研究正在推进基础科学和应用科学，为有关物质性质的基本问题提供答案，并通过改进通信，制造和传感技术为我们的生活方式提供有形和直接的好处。

Quantum mechanics is the universal mathematical language that we use to describe and predict the behavior of physical systems. While encompassing standard or so-called "classical" properties, the predictions of quantum mechanics also include exotic and surprising phenomena that are both challenging our ideas about the nature of reality and being exploited to improve society through better communication (quantum cryptography), data storage (quantum effects in solid state devices), inertial navigation (atom interferometers), and measurement technologies (quantum sensors).**The aim of this research program is to use laser-cooled gases to explore fundamental questions in many-body quantum phenomena and to use these gases to realize new quantum sensors with industrial and commercial relevance.**Technological breakthroughs in laser-cooling of atoms and molecules have created a new realm of ultra-low temperature science. At temperatures very near absolute zero (in the micro- to nano-kelvin range), these ultra-cold quantum materials offer us access to completely novel sensing elements and novel states of matter inaccessible by any other means. The unique detection methods and the degree of control available in these systems (including the ability to dynamically tune the particle-particle interactions, the particle density, and the confinement geometry), provide direct experimental access to some of the most important and fundamental phenomena of few and many-body quantum mechanics. Consider for example, the question "What are the collective behaviors of a system of strongly interacting quantum particles?" This question is central to understanding an array of physical systems of both fundamental and technological interest from the microscopic to the astronomical scale including quark-gluon plasmas, electrons in high-Tc superconductors, super-fluid liquid helium, ultra-cold atomic gases, and nucleons in neutron stars. Indeed, every physical object that exists, except for an elementary particle, is a many-body quantum system, and at present, theoretical understanding of strongly interacting many-body systems is still limited because interactions can make the particle-particle correlations dominate the behavior and then mean-field theory and perturbative analysis are inadequate. In order to advance fundamental knowledge and technology, it is essential to establish the validity of new theoretical approaches by comparing them with clean and reproducible experimental measurements. Ultra-cold atomic or molecular gases have already demonstrated that they are an ideal experimental testbed for this purpose because of the aforementioned degree of control, their reproducibility, and the wide array of measurement options they yield. In addition studying quantum materials, we aim to create new sensors where the sensor element itself is a quantum of matter (e.g. a single atom or a single molecule). Cold atoms have already been used to realize the most accurate and sensitive gravitational and inertial sensors with matter wave interferometry and to realize our primary frequency/time standard (an atomic fountain clock). We will begin with the development of a new sensor technology we recently demonstrated - the use of cold atoms to measure particle flux in an ultra-high vacuum. This technology is expected to impact, among other things, semi-conducting fabrication processes which rely on controlling particle densities and fluxes in vacuum. In these ways, research on cold atomic and molecular gases is advancing both fundamental and applied science providing answers to basic questions about the nature of matter and providing tangible and immediate benefits to our way of life by improved communication, fabrication, and sensing technologies.