Experiments with Quantum Gases of Lithium in 1, 2, and 3 Dimensions

超冷原子气体的研究随着捕获、冷却和操纵原子气体的能力的迅速发展而大大扩展，因此它们可以被应用于更好地理解凝聚态、材料、核和粒子物理中的复杂现象。原子气体可以被冷却到纳米开尔文状态，在那里原子的行为更像波而不是经典粒子。在这个“量子体系”中，原子表现出物理世界中已知的一些最惊人的现象，包括超流性，一种类似于超导性的现象，但中性原子取代了电子。与具有缺陷、杂质和随机无序的真实的材料不同，原子类似物本质上是干净的，并且非常可调，从而能够对基本模型进行高度可控的测试。根据这项资助进行的实验将使用超冷费米锂原子Li-6来模拟高温超导体的性质和特征，高温超导体是具有重要技术意义的材料，但仍然只有部分了解。该小组还将继续研究具有不相等自旋数的混合物的配对，以绘制出这个令人难以置信的丰富系统的相图。一个特别的焦点是“FFLO”阶段，其中配对发生在非零质心动量。FFLO相位已经在理论上研究了很长时间，但到目前为止还没有明确的实验观察。 这些实验将有望澄清与其他实验相分离的观察差异。 最后，利用锂的玻色子形式Li-7，该小组将研究安德森局域化，即由于无序而从超流体或导体到绝缘体的转变。 玻色子系统的第二个实验将探索最近提出的首次产生二维孤子的动态稳定方案。这项工作的更广泛影响是双重的：首先，对材料基本模型的更深入理解可能使设计具有改进性能的真实的材料成为可能，例如更高温度的超导体;二是为从事该研究的学生和博士后提供广泛的科学培训。

Research with ultracold atomic gases has greatly expanded by rapid advancement in the ability to trap, cool, and manipulate atomic gases, so that they may be applied to gain better understanding of complex phenomena in condensed matter, material, nuclear, and particle physics. Atomic gases can be cooled to the nano-Kelvin regime where atoms behave more as waves than as classical particles. In this "quantum regime," the atoms exhibit some of the most startling phenomenon known in the physical world, including superfluidity, an analog of superconductivity but with neutral atoms taking the place of electrons. Unlike real materials that possess defects, impurities, and random disorder, the atomic analogs are inherently clean and extraordinarily tunable enabling highly controllable tests of fundamental models. The experiments performed under this grant will use ultra-cold Fermionic lithium atoms, Li-6, to simulate the properties and characteristics of high-temperature superconductors, which are materials of great technological significance, but remain only partially understood. The group will also continue their studies of pairing of mixtures with unequal spin numbers to map out the phase diagram of this incredibly rich system. A particular focus is the "FFLO" phase, where pairing occurs with non-zero center of mass momentum. The FFLO phase has been long studied theoretically, but as of yet there are no clear experimental observations. These experiments will hopefully clarify differences in observations of phase separation with other experiments. Finally using a Bosonic form of lithium, Li-7, the group will investigate Anderson localization, the transition from a superfluid or conductor to an insulator due to disorder. A second experiment in the Boson system will explore a recently proposed dynamical stabilization scheme for creating two-dimensional solitons for the first time.The broader impact of this work is two-fold: firstly, greater understanding of fundamental models of materials may enable the design of real materials with improved performance, such as higher temperature superconductors; and secondly, this research will provide a broad scientific training for the students and post-doctoral scientists engaged in it.