Strongly Correlated Quantum Gases with Single Site Addressability

量子气体显微镜是在前三年的资助期内开发的，可以探测哈伯德制度光学晶格上的单个原子，具有单一晶格位置分辨率和接近单位保真度。这为原子量子气体研究打开了许多新的可能性。前所未有的成像保真度使人们有可能在单个粒子水平上探测量子气体，这应该允许人们直接识别强关联量子态，如Mott绝缘体。此外，光学分辨率可以用来创造任意的潜在景观，并以许多新的方式操纵量子气体。这项工作将涉及使用量子气体显微镜在强关联原子气体中进行非平衡物理实验。第一个目标是研究超流向Mott绝缘体转变的动力学，并表征非均匀体系中的熵流动。下一步是利用投射任意潜在景观的可能性来引入一个尖锐的潜在步骤。这一步骤形成了一个“结点”，每一侧都有不同的超流体或Mott绝缘域。改变台阶的高度或位置应该允许以一种定义明确的方式产生激发，为非均匀非平衡物理产生一种新的范式。在特定的区域中，这个系统可以映射到自旋1/2的海森堡模型上，该模型允许只使用单一成分的量子气体来研究磁性。最终目标是将最近演示的创建涡旋的方案扩展到量子气体显微镜，该方案应该允许以可重现的方式创建由多个拓扑准粒子(涡旋、天空微子和梅隆)组成的气体。这为研究这类准粒子的碰撞、相互作用和湮灭，以及随着强关联区或量子霍尔区的逼近而研究粒子动力学的变化提供了可能。所有这些实验都由量子气体显微镜独一无二地实现。这项工作将对研究、教育和技术产生广泛影响。这项新的实验将是世界范围内寻求通过实验实现物质的新的强关联量子态的重要一步，并有助于理解基本的凝聚态模型。这增加了一个跨学科的方面，因为预计这种进步将促进材料科学，并导致新材料的发展，如改进的超导、热电和磁性材料。这项研究本身将为研究生、本科生和博士后创造研究机会。PI正在开发一系列新的本科实验，并继续开发一门新的本科光学课程。研究生将使用通过这项研究获得的技能来开发这些课程的实验和课堂演示。这项研究产生的光学晶格中单个原子的图像和电影是将量子气体研究的魅力带给广大观众的独特方式。这些实验的图像和电影将被PI和一些同事在对普通观众的公开演讲和讲座中使用(并且已经使用)。

The quantum gas microscope, developed in the previous three-year grant period, allows detecting individual atoms on a Hubbard regime optical lattice with single lattice site resolution and near unity fidelity. This opens many new possibilities for atomic quantum gas research. The unprecedented imaging fidelity makes it possible to probe the quantum gas on a single particle level, which should allow one to directly identify strongly correlated quantum states such as Mott insulators. In addition, the optical resolution can be used for creating arbitrary potential landscapes, and to manipulate the quantum gas in many new ways. This work will involve using the quantum gas microscope to carry out experiments on non-equilibrium physics in a strongly correlated gas of atoms. The first goal is to study the dynamics of the superfluid to Mott insulator transition, and to characterize the flow of entropy in the inhomogeneous system. The next step is to use the possibility to project arbitrary potential landscapes for introducing a sharp potential step. The step forms a 'junction', with different superfluid or Mott insulating domains on each side. Changing the height or position of the step should allow creating excitations in a well defined way, generating a new paradigm for inhomogeneous non-equilibrium physics. In a specific regime, this system can be mapped on a spin 1/2 Heisenberg model, which allows studying magnetism using just a single component quantum gas. The final goal is to extend a recently demonstrated scheme for creating vortices to the quantum gas microscope, which should allow creating a gas of multiple topological quasi-particles (vortices, skyrmions, and merons) in a reproducible way. This opens the possibility to study collision, interactions, and annihilation of such quasi-particles, and to study the change in the particle dynamics as the strongly correlated regime or the quantum Hall regime is approached. All of these experiments are uniquely enabled by the quantum gas microscope. The work will have broad impact on research, education and technology. The new experiment will be an important step in the world-wide quest for the experimental realization of novel strongly correlated quantum states of matter, and help understand fundamental condensed matter models. This adds an interdisciplinary aspect, since it is expected that such advances would feed to material science and lead to the development of new materials such as improved superconducting, thermoelectric and magnetic materials. The research itself will generate research opportunities for graduate students, undergraduate students, and postdocs. The PI is developing a new undergraduate lab series, and continues to develop a new undergraduate optics course. Graduate students will use the skill acquired through this research to develop experiments and lecture demonstrations for these courses. Images and movies of single atoms in optical lattices as generated in this research are a unique way to bring the fascination of quantum gas research to a broad audience. Such images and movies of the experiment will be used (and have already been used) by the PI and by a number of colleagues in public talks and lectures to a general audience.