Pair Correlations in Atomic Bose Gases

原子玻色气体中的配对相关性

• 批准号: 453194772
• 负责人: Professor Dr. Claus Zimmermann
• 金额: --
• 依托单位: Physikalisches Institut
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/453194772?language=en
• 关键词: Pair; Correlations; Atomic; Bose; Gases

Pair correlations play a central role in the physics of interacting quantum gases. In atomic Bose and Fermi gases they can be varied over many orders of magnitude with the help of Feshbach resonances. This control is used in a variety of ways in current research and makes the field of atomic quantum gases extremely fruitful for a deeper understanding of quantum many-body systems.Until now, pair correlations could only be observed via the increased inelastic scattering losses associated with them. This method is very time-consuming, since for each data point a complete experimental cycle of several tens of seconds must be run through. The recording of meaningful spectra therefore requires several days to weeks. Last year, we developed a method that overcomes these problems and allows us to observe pair correlations in situ with a time resolution of less than 100 nanoseconds without destroying the atomic quantum gas. With the present proposal we want to further develop the method and apply it to two fundamental questions. The first issue concerns unitary Bose gases. Unitary Bose gases are quantum gases with maximum pair correlation at small distances. They are universal many-body systems whose properties depend only on the mass of the atoms and the particle density. Due to their fundamental importance, they are currently the subject of intensive experimental and theoretical research. We plan to use our method to study the dynamic properties of unitary Bose gases. For this purpose, the scattering length is periodically modulated and the change of the pair correlation observable directly in the ion signal is detected in situ and with high time resolution. In a second subproject we plan to use our method to detect Efimov trimers. In our Tübingen lithium-rubidium mixture we have investigated bound heteronuclear Efimov trimer states. Here, too, we were previously dependent on the extremely time-consuming and noisy observation of three-body losses. Efimov states consisting of one light atom (lithium) and two heavy atoms (rubidium) can be attributed to a two-body problem by adiabatically eliminating the fast dynamics of the light atom. This leads to an additional potential between the two heavy atoms. The resulting change in the pair correlation of the heavy atoms should be observable in the ion signal in situ and in real time.

对关联在相互作用量子气体的物理学中起着核心作用。在原子玻色和费米气体中，它们可以在费什巴赫共振的帮助下在许多数量级上变化。这种控制在目前的研究中有多种用途，使得原子量子气体领域在更深层次理解量子多体系统方面取得了极其丰硕的成果。到目前为止，对关联只能通过与之相关的增加的非弹性散射损失来观察到。这种方法非常耗时，因为对于每个数据点，必须经过几十秒的完整实验周期。因此，记录有意义的光谱需要几天到几周的时间。去年，我们开发了一种克服这些问题的方法，使我们能够在不破坏原子量子气体的情况下，以低于100纳秒的时间分辨率在原位观察对关联。通过目前的提议，我们希望进一步发展该方法，并将其应用于两个基本问题。第一个问题与单一玻色气体有关。酉玻色气体是在短距离内具有最大对关联的量子气体。它们是普遍存在的多体系统，其性质仅取决于原子的质量和粒子密度。由于它们的根本重要性，它们目前是密集的实验和理论研究的主题。我们计划用我们的方法来研究么正玻色气体的动力学性质。为此目的，周期性地调制散射长度，并以高时间分辨率在原位检测到在离子信号中可直接观测到的对关联的变化。在第二个子项目中，我们计划使用我们的方法来检测Efimov三聚体。在我们的Tübingen锂-Rb混合物中，我们研究了束缚异核Efimov三聚态。在这里，我们以前也依赖于极其耗时和嘈杂的三体损失观测。通过绝热消除轻原子的快动力学，由一个轻原子(锂)和两个重原子(Rb)组成的Efimov态可以归结为一个两体问题。这导致了两个重原子之间的附加势。由此产生的重原子对关联的变化应该可以在离子信号中原位和实时地观察到。