Strongly Interacting Quantum Mixtures of Ultracold Atoms

电子运行着我们的现代世界：它们穿过我们的灯泡，智能手机，笔记本电脑和电视屏幕。但值得注意的是，我们根本不了解它们是如何协同工作的。我们知道电子遵守量子力学的规则：它们可以像波而不是台球一样传播，而且一个基本原理禁止两个电子在同一个波中。但是，如果我们了解整个电子集合的一般行为，我们就可以设计出携带电力而没有任何损失的材料。笔记本电脑和智能手机不会发热，我们不会浪费能源，可以运行整个国家只是为了在城市之间传输电力，在更基本的层面上，我们会理解物质本身的结构。本项目旨在解决这些问题。 该项目将使用原子作为电子和其他基本粒子的替身，以寻找物质的新集体状态。特别是，该项目旨在揭示在一般情况下发生无损耗传输的规则，包括物质的超流体状态-原子无摩擦流动-以及存在高磁场时集体流动的新状态。本项目将对热力学进行精确研究，玻色子（Na）和费米子强相互作用混合体的集体激发和输运性质（40 K和6Li），目的是揭示费米子物质的新状态：从玻色子诱导的超流性，自旋不平衡混合物中的非均匀超流性，到费米子和玻色子分子的量子霍尔态。Feshbach散射共振将用于调整粒子间的相互作用，并将采用光学盒势来实现均匀的密度。自旋、声音和热量的传输将使用新的探测方法进行，例如，热量的传播将直接成像。现场观测的激励，如涡流和孤子将允许调查其稳定性作为一个功能的物种组成和有效磁场。比较理论计算，如果他们存在，将作出，这应该推进我们的理解强相互作用的费米systems.This奖项反映了NSF的法定使命，并已被认为是值得的支持，通过评估使用基金会的智力价值和更广泛的影响审查标准。

Electrons run our modern world: They zip through our light bulbs, smart phones, laptops, and TV screens. But remarkably, we do not understand fundamentally how they work together. We know electrons obey the rules of quantum mechanics: They can propagate as waves rather than billiard balls, and a fundamental principle forbids two of them to be in one and the same wave. But if we understood how an entire collection of electrons behaved in general, we could design materials that carry electricity without any loss. Laptops and smart phones would not heat up, we would not waste energy that could run entire countries just to transmit power between cities, and on an even more fundamental level we would understand the fabric of matter itself. This present project is designed to address these very points. The project will use atoms as stand-ins for electrons and other elementary particles to search for novel collective states of matter. In particular, the project aims to uncover the rules by which loss-less transport can occur in general settings, including superfluid states of matter - where atoms flow without friction - and novel states of collective flow in the presence of high magnetic fields.The present project will perform precision studies of the thermodynamics, collective excitations and transport properties of strongly interacting mixtures of bosons (Na) and fermions (40K and 6Li), with the goal of uncovering novel states of fermionic matter: From boson-induced superfluidity, inhomogeneous superfluidity in spin-imbalanced mixtures, to quantum Hall states of fermions and bosonic molecules. Feshbach scattering resonances will be used to tune interparticle interactions, and optical box potentials will be employed to realize homogeneous densities. Transport of spin, sound and heat will be performed using novel detection methods, e.g. the propagation of heat will be directly imaged. In-situ observations of excitations such as vortices and solitons will allow investigation of their stability as a function of species composition and effective magnetic fields. Comparisons to theoretical calculations, where they exist, will be made, which should advance our understanding of strongly interacting Fermi systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.