JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA.
Université Paris-Saclay, CNRS, Laboratoire Aimé Cotton, 91405 Orsay, France.
Science. 2020 Dec 11;370(6522):1324-1327. doi: 10.1126/science.abe7370.
Full control of molecular interactions, including reactive losses, would open new frontiers in quantum science. We demonstrate extreme tunability of ultracold chemical reaction rates by inducing resonant dipolar interactions by means of an external electric field. We prepared fermionic potassium-rubidium molecules in their first excited rotational state and observed a modulation of the chemical reaction rate by three orders of magnitude as we tuned the electric field strength by a few percent across resonance. In a quasi-two-dimensional geometry, we accurately determined the contributions from the three dominant angular momentum projections of the collisions. Using the resonant features, we shielded the molecules from loss and suppressed the reaction rate by an order of magnitude below the background value, thereby realizing a long-lived sample of polar molecules in large electric fields.
对分子相互作用（包括反应性损耗）的完全控制将为量子科学开辟新的前沿。我们通过外部电场诱导共振偶极相互作用，展示了超冷化学反应速率的极端可调性。我们在其第一激发转动态下制备了费米子钾-铷分子，并在共振时通过调节电场强度几个百分点观察到化学反应速率的三个数量级的调制。在准二维几何形状中，我们准确地确定了碰撞中三个主要角动量投影的贡献。利用共振特征，我们使分子免受损耗，并将反应速率抑制在背景值以下一个数量级，从而在大电场中实现了长寿命的极性分子样品。
