玻色性 $^{39}$K-$^{133}$Cs 与 $^{41}$K-$^{133}$Cs 混合物的同时亚多普勒激光冷却与光俘获

中文摘要 AI 辅助

我们报道了 $^{39}$K-Cs 和 $^{41}$K-Cs 混合物的同时亚多普勒冷却与光偶极俘获。两种混合物均被冷却至约 $10$ $\mathrm{\mu}$K 的温度，达到了与每种物质单独冷却时相当的性能。据我们所知，这是首次实现激光冷却并光俘获 $^{41}$K-Cs 混合物。对于 $^{39}$K-Cs 混合物，我们还通过斯特恩-盖拉赫分离实现了并行的自旋分辨费什巴赫光谱。对于钾同位素，我们采用 $D_1$ 线灰度胶状物（gray molasses）实现亚多普勒冷却，而对于铯，整个冷却序列均使用 $D_2$ 跃迁实现。我们将原子自旋极化，并将玻色-玻色混合物约束在 1064 nm 光偶极阱中。利用所得的 $^{39}$K-Cs 样品，我们观察到 14 个异核费什巴赫损失特征。其中 5 个与先前报道的共振一致，而据我们所知，有 9 个此前未在实验中被观察到，包括 $p$ 波特征和额外自旋通道中的共振。$^{41}$K-Cs 混合物在光偶极阱中的较短寿命目前阻碍了系统性的费什巴赫光谱研究，因此我们在本工作中未进行该研究。为了定量表征这一限制，我们在可比的温度和密度条件下研究了 $^{39}$K-Cs 和 $^{41}$K-Cs 混合物的衰变动力学，揭示了 $^{41}$K-Cs 混合物中显著更强的非指数损失。所展示的超冷 $^{41}$K-Cs 混合物的制备为这一此前未探索的同位素体的费什巴赫共振和光缔合光谱提供了起点。这些测量对于确定磁缔合和相干光学转移的合适路径至关重要，并最终对于产生超冷基态 $^{41}$KCs 分子至关重要。

英文摘要

We report simultaneous sub-Doppler cooling and optical dipole trapping of $^{39}$K-Cs and $^{41}$K-Cs mixtures. Both mixtures are cooled to temperatures $\sim10$ $\mathrmμ$K, achieving performance comparable to that obtained with each species individually. To the best of our knowledge, this constitutes the first realization of a laser-cooled and optically trapped $^{41}$K-Cs mixture. For the $^{39}$K-Cs mixture, we additionally implement parallel spin-resolved Feshbach spectroscopy enabled by Stern-Gerlach separation. For potassium isotopes, we implement sub-Doppler cooling with $D_1$-line gray molasses, while for cesium the entire cooling sequence is implemented using $D_2$ transitions. We spin-polarize the atoms and confine Bose-Bose mixtures in a 1064 nm optical dipole trap. Using the resulting $^{39}$K-Cs samples, we observe 14 heteronuclear Feshbach loss features. Five agree with resonances reported previously, while nine have, to the best of our knowledge, not been observed experimentally before, including $p$-wave features and resonances in additional spin channels. The shorter lifetime of the $^{41}$K-Cs mixture in the optical dipole trap currently hinders systematic Feshbach spectroscopy, which we therefore do not pursue in this work. To characterize this limitation quantitatively, we study the decay dynamics of $^{39}$K-Cs and $^{41}$K-Cs mixtures under comparable temperature and density conditions, revealing a substantially stronger nonexponential loss in the $^{41}$K-Cs mixture. The demonstrated preparation of ultracold $^{41}$K-Cs mixtures provides a starting point for Feshbach-resonance and photoassociation spectroscopy of this previously unexplored isotopologue. Such measurements are essential for identifying suitable pathways for magnetoassociation and coherent optical transfer, and ultimately for the production of ultracold ground-state $^{41}$KCs molecules.

发表机构

• Institute of Experimental Physics, University of Warsaw（华沙大学实验物理研究所）
• Durham University（杜伦大学）
• Stockholm University（斯德哥尔摩大学）
• eleQtron GmbH（eleQtron有限公司）
• Warsaw University of Technology（华沙理工大学）

机构由 AI 辅助整理，请以论文原文为准。