CAREER: Two-Dimensional Quantum Fabric of Ultracold Dipolar Molecules

理解和控制材料的基本性质是物理学的一个主要前沿。从工业革命中的淬火钢到电子时代使用的掺杂硅，理解和控制材料的新方法往往会带来新的技术。从物理学的角度来看，材料通常是由密集堆积的原子组成的，原子的离子核心带正电荷，离子核心被带负电荷的电子气渗透。我们知道电子和离子的运动是受量子力学支配的。然而，准确地理解这种运动是如何产生超导和奇异形式的磁性等材料性质的，是一个重大挑战。这很有挑战性，部分原因是很难观察到单个电子。它们很小；它们移动得很快；它们相互作用，很容易受到干扰。为了用一种新的方法来应对这一挑战，该项目旨在使用真空中的超冷分子气体来模拟材料中的电子。分子之间的相互作用有望使结晶相自组织等现象更容易观察到。这个团队将在超低温下逐个原子地组装极性分子，然后将分子捕获在一张薄薄的激光中。虽然分子被限制在一维空间中，但它们仍然可以在两个维度上自由移动并相互作用。该项目将探索如何利用这种偶极分子的量子力学“组构”来模拟真实材料的性质，并研究物质的基本组织原理。该团队将建造一种新的设备来研究超冷偶极分子的二维量子系统。目标包括(1)创造一种新的钠和铯原子的量子气体混合物。(2)绝对基态钠铯分子的致密超冷样品的产生。(3)通过高分辨率成像研究单一二维薄片中的分子气体。钠铯分子有很大的电偶极矩(在化学上稳定的双碱分子中最大)。利用分子的偶极矩，这个团队的目标是探索迄今为止无法获得的参数体系，这些参数体系可能使人们能够观察到新的多体量子相，如强关联的超流动性、超固体和偶极晶体的形成。除了技术上的努力，该项目还伴随着一个广泛的推广计划，旨在提高高中生、本科生和高中科学教师在量子物理方面的素养。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Understanding and controlling fundamental properties of materials is a major frontier of physics. From hardened steel in the industrial revolution to the doped silicon used in the electronics era, new ways to understand and control materials often leads to new technology. In a physics perspective, materials are generally made of densely packed atoms with positively charged ionic cores permeated by a negatively charged gas of electrons. We know the movement of electrons and ions is governed by quantum mechanics. However, understanding exactly how this motion gives rise to material properties such as superconductivity and exotic forms of magnetism is a major challenge. This is challenging, in part, because it is difficult to observe individual electrons. They are small; they move quickly; they interact with each other, and they are easily disturbed. To address this challenge with a new approach, this project aims to use gasses of ultracold molecules in vacuum to simulate electrons in materials. Interactions between molecules are expected to make phenomena such as the self-organization of crystalline phases easier to observe. This team will assemble polar molecules atom-by-atom at ultracold temperatures and then trap molecules in a thin sheet of laser light. While confined in one dimension, the molecules will still be free to move in two dimensions and interact with each other. This project will explore how to use this quantum mechanical "fabric" of dipolar molecules to simulate properties of real materials and to study fundamental organizing principles of matter.The team will construct a new apparatus to study two-dimensional quantum systems of ultracold dipolar molecules. The objectives include (1) the creation of a novel quantum gas mixture of sodium and cesium atoms. (2) The creation of dense ultracold samples of sodium-cesium molecules in the absolute ground state. (3) The investigation of molecular gases in a single two-dimensional sheet via high-resolution imaging. Sodium-cesium molecules have a large electric dipole moment (the largest among the chemically stable bialkali molecules). Utilizing the molecules' dipole moment, this team aims to explore parameter regimes that were inaccessible so far, and which may enable the observation of novel many-body quantum phases such as strongly correlated superfluidity, supersolidity, and the formation of a dipolar crystal. In addition to the technical effort, the project is accompanied by a broad outreach program that aims to improve literacy in quantum physics among high school students, undergraduate students, and high school science teachers.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.