标题： 超冷偶极分子自束缚液滴的观察 显示英文标题

标题： Observation of Self-Bound Droplets of Ultracold Dipolar Molecules

摘要： 超冷偶极分子气体长期以来被视为实现新型量子相态的平台。碰撞屏蔽技术的进展，保护分子免受非弹性损耗，使得简并费米气体的制备成为可能，并且最近实现了偶极分子的玻色-爱因斯坦凝聚。然而，到目前为止，在由偶极-偶极相互作用驱动的超冷分子气体中观察到量子相态仍然难以实现。在本工作中，我们报告了在强偶极钠-铯分子超冷气体中自束缚液滴和液滴阵列的形成。从分子玻色-爱因斯坦凝聚（BEC）开始，微波调节场被用来诱导具有可调强度和各向异性的偶极-偶极相互作用。通过改变相互作用诱导的速度，覆盖四个数量级的动力学范围，我们在平衡和非平衡条件下制备液滴，观察到从坚固的一维（1D）阵列到波动的二维（2D）结构的转变。液滴的密度高达初始BEC的100倍，达到强相互作用 regime，并暗示了量子液体或晶体态的可能性。这项工作确立了超冷分子作为探索强偶极量子物质的系统，并为在光晶格中实现自组织晶体相和偶极自旋液体打开了大门。 显示英文摘要

摘要： Ultracold gases of dipolar molecules have long been envisioned as a platform for the realization of novel quantum phases. Recent advances in collisional shielding, protecting molecules from inelastic losses, have enabled the creation of degenerate Fermi gases and, more recently, Bose-Einstein condensation of dipolar molecules. However, the observation of quantum phases in ultracold molecular gases that are driven by dipole-dipole interactions has so far remained elusive. In this work, we report the formation of self-bound droplets and droplet arrays in an ultracold gas of strongly dipolar sodium-cesium molecules. Starting from a molecular Bose-Einstein condensate (BEC), microwave dressing fields are used to induce dipole-dipole interactions with controllable strength and anisotropy. By varying the speed at which interactions are induced, covering a dynamic range of four orders of magnitude, we prepare droplets under equilibrium and non-equilibrium conditions, observing a transition from robust one-dimensional (1D) arrays to fluctuating two-dimensional (2D) structures. The droplets exhibit densities up to 100 times higher than the initial BEC, reaching the strongly interacting regime, and suggesting the possibility of a quantum-liquid or crystalline state. This work establishes ultracold molecules as a system for the exploration of strongly dipolar quantum matter and opens the door to the realization of self-organized crystal phases and dipolar spin liquids in optical lattices.