玻色分子的静态场屏蔽：蒸发至简并态与自束缚液滴
Static-Field Shielding of Bosonic Molecules: Evaporation to Degeneracy and Self-Bound Droplets
- Princeton University（普林斯顿大学）
- TU Wien（维也纳工业大学）
- Laboratoire Kastler Brossel, Collège de France, CNRS, ENS-PSL University, Sorbonne Université（卡斯勒布罗塞尔实验室，法兰西学院，法国国家科学研究中心，巴黎文理研究大学，索邦大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过静态场Förster屏蔽将玻色$^{23}$Na$^{87}$Rb分子的两体损耗抑制四个数量级，高效蒸发后用7200个分子达到简并态，还观察到源自简并或非简并母气体的自束缚液滴，模拟与实验结果吻合，确立了该屏蔽作为制备玻色极性分子简并气体与自束缚液滴的单场途径。
AI中文摘要：
超冷分子具有强且可调的偶极相互作用，是量子多体物理的有力平台，但通过蒸发冷却达到简并态需要抑制非弹性碰撞。微波碰撞屏蔽已实现极性分子的简并费米气体与玻色-爱因斯坦凝聚体制备，而静态电场屏蔽仅局限于费米子物种，这类物种非弹性损耗概率较低。我们演示了玻色$^{23}$Na$^{87}$Rb分子的静态场Förster屏蔽，将两体损耗抑制了多达四个数量级。在无束缚态的电场窗口内，三体损耗也被强烈抑制，实现了高效蒸发。以2.09(9)的效率蒸发后，我们将气体的相空间密度提升了两个数量级，用7200(1000)个分子达到简并态。我们在蒸发结束后，于宽电场强度范围内观察到自束缚液滴，这些液滴源自简并或非简并母气体。我们开展了路径积分蒙特卡罗模拟，结果表明所观察到的液滴具有丝状本质，且与实验观测的液滴形成温度吻合良好。我们的研究确立了Förster屏蔽作为一种单场途径，可用于制备玻色极性分子的简并气体与自束缚液滴。
英文摘要：
The strong, tunable dipolar interactions of ultracold molecules make them a powerful platform for quantum many-body physics, but reaching degeneracy by evaporative cooling requires suppressing inelastic collisions. Microwave collisional shielding has enabled the preparation of degenerate Fermi gases and Bose-Einstein condensates of polar molecules, whereas static electric field shielding has been limited to fermionic species, which are less prone to inelastic loss. We demonstrate static-field Förster shielding of bosonic $^{23}$Na$^{87}$Rb molecules, suppressing two-body loss by up to four orders of magnitude. Within a bound-state-free electric-field window, three-body loss is also strongly suppressed, enabling efficient evaporation. Evaporating with an efficiency of 2.09(9), we increase the phase-space density of the gas by two orders of magnitude, reaching degeneracy with 7200(1000) molecules. We observe self-bound droplets at the end of evaporation over a wide range of field strengths, emerging from either degenerate or non-degenerate parent gases. We perform Path Integral Monte Carlo simulations, which suggest that the observed droplets are filamentary in nature, and find good agreement with the experimentally observed droplet formation temperatures. Our results establish Förster shielding as a single-field route to prepare degenerate gases and self-bound droplets of bosonic polar molecules.
