Strong correlations in multi-component quantum gases

多组分量子气体中的强相关性

• 批准号: 46321975
• 负责人: Professor Dr. Klaus Sengstock
• 金额: --
• 依托单位: Institut für Laser-Physik
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/46321975?language=en
• 关键词: Strong; correlations; multi; component; quantum

The investigation of intriguing physical effects provoked by strong correlations in ultracold quantum gases has matured into a very active field of research at the interlink between atomic and condensed matter physics. The Research Unit FOR801 precisely acts at this interface and contributes to the international development.The exceptional control available in systems of ultracold atoms allows for the realization of a whole wealth of model Hamiltonians often originally invoked in the context of solid state physics. The opportunity to prepare very clean, defect-free systems in hand with the tunability of particle interaction, lattice parameters and dimensionality opens up the possibility to accurately test predictions of underlying theoretical models which are at the heart of condensed matter physics, the Bose-Hubbard model being one of the most prominent examples.Within the first funding period of this Forschergruppe considerable progress in preparing and detecting thus far unexplored strongly correlated quantum gas systems has been obtained in the Hamburg group. The ability to enter the regime of strong correlations in triangular and hexagonal lattice geometries as well as the implementation of fully momentum-resolved Bragg spectroscopy to explore and identify novel phases and excitations are two of the fundamental achievements in this context.In the second funding period we intend to continuatively investigate strongly correlated Spinor systems as well as Fermi-Bose mixtures in different kinds of lattice geometries and dimensionalities. This work will greatly benefit from the experimental achievements obtained in the first period and the concise collaboration with the theory and experimental groups in the Research Unit FOR801. Mutually beneficial development of theoretical descriptions suiting our experimental preconditions and techniques constitute a promising basis to prepare, identify and explore more complex phases of the multi-flavour quantum gas systems under consideration.In particular we will focus on the physics of Spinor condensates confined in a hexagonal optical lattice. We have recently investigated for the very first time the interesting aspects of an mF-dependent thus “magnetic” hexagonal lattice structure. Spin-dependent localization together with coherent collisional spin dynamics might give rise to interesting new effects like state-dependent phase transitions, a blockade of tunnelling and spin entanglement and transport. The first results clearly motivate to further study these systems and to obtain an in-depth understanding of the underlying physics and opportunities concerning quantum simulations within the second funding period. Transport properties in triangular and hexagonal lattices which are expected to be conceptually different from hyper- cubic lattices will be investigated and as a long-term goal we plan to study the physics of higher orbital system in hexagonal lattices promising the existence of frustrated new phases.A second central point within this project will be the investigation of novel phases of Fermi-Bose mixtures in optical lattices as a direct continuation of the experimental and theoretical work performed by the Hamburg group in the first funding period. Interesting phenomena such as the formation of charge density waves or the existence of quasi-particles such as polarons are predicted to occur in these mixed systems and shall be realized and studied in detail in the framework of this project. Fully momentum-resolved Bragg spectroscopy incorporated in the first three years of this Research Unit will serve as a tool to unambiguously identify these correlated many-body states. Furthermore we plan to set up a new three beam lattice, similar to that used to study Spinor condensates, for the Fermi-Bose experiment to grant access to thus far unexplored physical phenomena in the context of strongly correlated systems, i.e. grapheme-like physics in a hexagonal optical lattice. These investigations will be in close analogy to topics vividly discussed in condensed matter physics where exotic superconducting states and the influence of orbital effects are of highest interest. As a long-term goals our profound experience in the field of Spinor BEC shall be extended to spin-changing dynamics and more generally spin-dependent phenomena of fermionic systems in optical lattices.

超冷量子气体中强关联引起的有趣物理效应的研究已经发展成为原子物理和凝聚态物理之间相互联系的一个非常活跃的研究领域。研究单元FOR 801正是在这个接口上工作，并为国际发展做出贡献。超冷原子系统中的特殊控制允许实现最初在固态物理学背景下经常调用的大量模型哈密顿量。准备非常干净，无缺陷的系统与粒子相互作用，晶格参数和维度的可调性的机会开辟了准确测试基础理论模型预测的可能性，这些模型是凝聚态物理学的核心，玻色-哈伯德模型是最突出的例子之一。在该研究小组的第一个资助期内，迄今为止在准备和检测方面取得了相当大的进展。在Hamburg群中得到了一个未被探索的强关联量子气体系统。在三角形和六边形晶格几何结构中进入强关联机制的能力以及实施完全动量分辨布拉格光谱来探索和识别新的相位和激发是这方面的两个基本成就。在第二个资助期内，我们打算继续研究强关联旋量系统以及费米-费米系统。不同晶格几何和维数的玻色混合物。这项工作将大大受益于第一阶段取得的实验成果，以及与FOR 801研究单元的理论和实验小组的简明合作。适合我们实验前提和技术的理论描述的互利发展构成了一个有前途的基础，准备，识别和探索更复杂的相的多味量子气体systems. In特别是，我们将专注于物理旋量凝聚体限制在一个六角光学晶格。最近，我们第一次调查了有趣的方面的mF依赖，因此“磁性”的六方晶格结构。自旋相关的局域化与相干碰撞自旋动力学一起可能会引起有趣的新效应，如状态相关的相变，隧道和自旋纠缠和运输的封锁。第一批结果清楚地激励进一步研究这些系统，并在第二个资助期内深入了解量子模拟的基础物理和机会。我们将研究三角晶格和六角晶格中的输运性质，这在概念上与超立方晶格不同，作为一个长期目标，我们计划研究六角晶格中的高轨道系统的物理，希望存在受抑的新相。光学晶格中的玻色混合物是汉堡小组在第一个资助期内进行的实验和理论工作的直接延续。有趣的现象，如电荷密度波的形成或准粒子，如极化子的存在，预计将发生在这些混合系统中，并应实现和详细研究在这个项目的框架。完全动量分辨布拉格光谱学纳入本研究单位的前三年将作为一种工具，明确识别这些相关的多体状态。此外，我们计划建立一个新的三束晶格，类似于用于研究旋量凝聚，费米-玻色实验，以获得迄今为止尚未探索的物理现象的背景下，强关联系统，即grapheme-like物理在一个六边形的光学晶格。这些研究将与凝聚态物理学中生动讨论的主题非常相似，其中奇异的超导态和轨道效应的影响是最感兴趣的。作为一个长期的目标，我们在旋量BEC领域的丰富经验将扩展到自旋变化动力学和更普遍的自旋相关现象的费米子系统的光学晶格。