Creating a gas of ultracold ion pairs out of long-range Rydberg molecules

用长程里德堡分子创造超冷离子对气体

• 批准号: 428456632
• 负责人: Professor Dr. Johannes Deiglmayr
• 金额: --
• 依托单位: Felix-Bloch-Institut für Festkörperphysik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/428456632?language=en
• 关键词: Creating; gas; ultracold; ion; pairs

The goal of this proposal is the exploration of a new approach to create a strongly-coupled neutral plasma. Strongly-coupled neutral plasmas consist of an equal number of positive and negative charges, whose interaction strength is much stronger than the thermal energy of the system. These plasmas exhibit strong spatial correlations between the charged particles. The many-body physics of such systems plays an important role in the core of gas-planets or fusion devices.The central idea of this project is the transformation of an ultracold gas of cesium atoms into a cesium-ion and –anion plasma. In a first step, pairs of ground-state atoms will be transformed into a longrange Rydberg molecule by absorption of a photon (photoassociation). The binding of such a molecule results from the scattering of the almost-free Rydberg electron off a ground-state atom within its orbit. The molecular states will be chosen such that their binding is dominated by scattering in a channel with a single quantum of angular momentum (p-wave scattering). In this case, dipole-allowed transitions exist between the scattering state of the electron-neutral system and the bound ground state of the cesium-anion.In a next step, the long-range Rydberg molecule will be transformed into an ion-pair state by stimulated emission, driven from a laser pulse in the mid infra-red. The ion-pair state is a bound state of an ion and an anion, whose properties are dominated by the Coulumb interaction between the charged particles. Because the Hamiltonian of system corresponds to the one of a Rydberg atom, the binding energies of the vibrational states of the ion-pair will also be described by Rydberg’s formula. Because the reduced mass of the ion-anion system is much larger than the one of an electron-ion system, these molecules are called “heavy-Rudberg molecules”. In a last step, the dissociation of heavy-Rydberg molecules into a free ion-anion pair will be investigated. The combination of all three steps will thus convert a gas of ultracold atoms into a gas of ultracold ions and anions.

这项提议的目标是探索一种创造强耦合中性等离子体的新方法。强耦合中性等离子体由数目相等的正电荷和负电荷组成，它们的相互作用强度远远大于系统的热能。这些等离子体在带电粒子之间表现出很强的空间相关性。这类系统的多体物理在气体行星或聚变装置的核心中起着重要作用。该项目的中心思想是将铯原子的超冷气体转化为铯离子和-阴离子等离子体。在第一步中，基态原子对将通过光子的吸收（光缔合）转变为长程里德伯分子。这种分子的结合是由几乎自由的里德伯电子从其轨道内的基态原子散射而来的。分子状态的选择将使它们的结合受到具有单量子角动量的通道中的散射（p波散射）的支配。在这种情况下，偶极允许跃迁存在于电子中性系统的散射态和铯阴离子的束缚基态之间。下一步，在中红外激光脉冲的驱动下，远程里德伯分子将被激发发射转化为离子对状态。离子对态是离子和阴离子的结合态，其性质由带电粒子之间的库仑相互作用决定。因为系统的哈密顿量与里德伯原子的哈密顿量相对应，所以离子对振动态的结合能也可以用里德伯公式来描述。由于离子-阴离子体系的约简质量比电子-离子体系的约简质量大得多，这些分子被称为“重拉德伯格分子”。在最后一步，重里德伯分子解离成一个自由的离子-阴离子对将被研究。这三个步骤的结合将把由超冷原子组成的气体转变成由超冷离子和阴离子组成的气体。