Dipolar quantum gases of strongly magnetic atoms

强磁性原子的偶极量子气体

• 批准号: 287321319
• 负责人: Professorin Dr. Francesca Ferlaino, Ph.D.
• 金额: --
• 依托单位: Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/287321319?language=en
• 关键词: Dipolar; quantum; gases; strongly; magnetic

This project aims at investigating dipolar effects in the few- and many-body physics using quantum degenerate gases of magnetic atoms. More precisely, our experiment uses atomic erbium, member of the lanthanide family, which counts among the most magnetic species of the periodic table. The choice of erbium has the advantage of combining the richness of the dipole-dipole interaction together with the extended knowhow of the ultracold atomic gas community, as well as the particular features of the lanthanide atoms. Within the next years, we will build on the knowledge and control gained on such systems, and deepen them, in the aim to unveil new aspects of dipolar quantum phenomena. We aim to investigate two very different types of systems: On the one hand, we will study dipolar Bose-Einstein condensates (BECs) in anisotropic geometries. Here our focus will be on the spectrum of elementary excitations of these systems and our aim a better understanding of the physics related to a special excitation, forming a minimum in energy at a large momentum, the so-called roton mode. By studying the full spectrum, we want to unveil how the roton mode softens when the interaction are tuned, how this depends on the system geometry and how this leads to distinct beyond-mean field effects does. We will also study how does the BEC’s excitation spectrum connects to the apparition of the recently discovered droplet states when reaching a dipolar dominated regime. Our overall goal in this first part is to understand if the BEC can connect in some way to special ground states, in particular the debated supersolid state, showing simultaneously superfluid and crystalline properties.On the other hand, we will focus on a quantum system formed by a mixture of two fermionic spin states of erbium. We have recently shown our ability to produce such mixtures and to tune their interactions. Our aim will now be to realize and study superfluid pairings in this new system. By tuning the interaction, one could cross from a superfluid of delocalized pairs formed along a Bardeen-Cooper-Schrieffer type of mechanism to a BEC of bound fermions. While such a crossover has been studied for years in alkali gases, erbium brings an exceptional scattering scenario, including dipole-dipole interactions, anisotropic short range interactions and multi-channel resonant scattering. Our aim is to reveal how these few-body features modify the behavior of the fermions assemblies at a many-body level.

这个项目的目的是利用磁性原子的量子简并气体来研究少数和多体物理中的偶极效应。更准确地说，我们的实验使用了元素周期表中磁性最强的元素之一--镧系元素家族的成员--原子铒。选择铒的好处是将丰富的偶极-偶极相互作用与超冷原子气体社区的广泛知识以及稀土原子的特殊特征结合在一起。在接下来的几年里，我们将在这些系统上获得的知识和控制的基础上，并深化它们，目的是揭示偶极量子现象的新方面。我们的目标是研究两类非常不同的系统：一方面，我们将研究各向异性几何中的偶极玻色-爱因斯坦凝聚体(BEC)。这里我们的重点将集中在这些系统的基本激发谱上，我们的目的是更好地理解与特殊激发有关的物理，在大动量下形成能量的最小值，即所谓的Roton模。通过对全谱的研究，我们想要揭示当相互作用被调谐时，旋子模是如何软化的，这是如何依赖于系统几何结构的，以及这如何导致明显的超出平均场效应的。我们还将研究当达到偶极主导区域时，BEC的激发光谱如何与最近发现的液滴状态的显现相联系。我们在第一部分的总体目标是了解BEC是否能以某种方式连接到特殊的基态，特别是有争议的超固体状态，同时显示出超流和结晶性质。另一方面，我们将关注由两个费米子自旋态组成的Er3+的量子系统。我们最近展示了我们生产这种混合物并调整其相互作用的能力。我们现在的目标是认识和研究这一新系统中的超流配对。通过调节相互作用，人们可以从沿着Bardeen-Cooper-Schrieffer类型的机制形成的离域对的超流体到束缚费米子的BEC。虽然这种交叉在碱性气体中已经被研究了多年，但铒带来了一种特殊的散射场景，包括偶极-偶极相互作用、各向异性短程相互作用和多通道共振散射。我们的目标是揭示这些少体特征如何在多体水平上改变费米子组件的行为。