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。从工业革命中的硬化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技术。从物理学的角度来看，材料通常由密集堆积的原子组成，带正电的离子核被带负电的电子气体渗透。 我们知道电子和离子的运动是由量子力学控制的。 然而，准确理解这种运动如何产生超导性和奇异形式的磁性等材料特性是一个重大挑战。 这是具有挑战性的，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，它们很容易被打扰。 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诸如结晶相的自组织等现象更容易观察。 该团队将在超低温下一个原子一个原子地组装极性分子，然后将分子捕获在一张激光薄片中。 虽然被限制在一维中，但分子仍然可以在二维中自由移动并相互作用。该项目将探索如何利用偶极分子的量子力学“织物”来模拟真实的材料的性质，并研究物质的基本组织原理。该团队将构建一个新的装置来研究超冷偶极分子的二维量子系统。目标包括：（1）创造一种钠和铯原子的新型量子气体混合物。(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个二维薄片中的分子气体。钠铯分子具有大的电偶极矩（在化学稳定的双碱分子中最大）。利用分子的偶极矩，该团队的目标是探索迄今为止无法访问的参数机制，这可能使观察到新的多体量子相，如强相关的超流性，超固体性和偶极晶体的形成。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的量子物理素养。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

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.