标题： 用二维库仑晶体模拟异构化 显示英文标题

标题： Emulating isomerization with two-dimensional Coulomb crystals

摘要： 异构化，即不同分子构型之间的重排，是化学中的基本过程。在这里，我们展示了二维库仑晶体可以模拟分子异构化，并用于表征其物理机制。在我们的分子类似物中，限制势作为电子轨道，可以连续和动态地调节。我们使用由六个138Ba+离子组成的平面晶体，其表现出两种稳定的构型，这取决于谐波捕获势的纵横比。通过改变这个纵横比，我们直接修改离子晶体的势能面（PES），并以受控方式触发异构化。我们确定了两种异构体之间的双稳态区域，并使用构型分辨成像实时检测异构化。使用蒙特卡洛模拟计算双势阱PES。通过比较模拟的转变速率与实验的种群比例，我们估计了晶体的温度。此外，我们通过快速淬火PES制备亚稳态构型，并以亚毫秒分辨率检测异构化动力学。我们的工作建立了一个新的平台来模拟分子过程，为研究晶体构型的量子叠加以及控制二维库仑晶体中的异构激发铺平了道路。 显示英文摘要

摘要： Isomerization, i.e. the rearrangement between distinct molecular configurations, is a fundamental process in chemistry. Here we demonstrate that two-dimensional Coulomb crystals can emulate molecular isomerization and be used to characterize its physical mechanisms. In our molecular analogue, the confining potential acts as an electronic orbital, which can be tuned continuously and dynamically. We use a planar crystal of six 138Ba+ ions, which exhibits two stable configurations depending on the aspect ratio of the harmonic trapping potential. By changing this aspect ratio, we directly modify the potential energy surface (PES) of the ion crystal, and trigger isomerization in a controlled way. We identify a region of bistability between the two isomers, and use configuration-resolved imaging to detect isomerization in real time. A Monte Carlo simulation is used to calculate the double well PES. By comparing simulated transition rates with experimental population ratios, we estimate the crystal's temperature. Additionally, we prepare metastable configurations by rapidly quenching the PES, and detect isomerization dynamics with sub-millisecond resolution. Our work establishes a new platform for emulating molecular processes, paving the way for studying quantum superpositions of crystal configurations, and for controlling isomeric excitations in two-dimensional Coulomb crystals.