University of California and California Institute for Quantum Emulation, Santa Barbara, CA, 93106, USA.
Nat Commun. 2018 May 25;9(1):2065. doi: 10.1038/s41467-018-04556-3.
Ultrafast electronic dynamics are typically studied using pulsed lasers. Here we demonstrate a complementary experimental approach: quantum simulation of ultrafast dynamics using trapped ultracold atoms. Counter-intuitively, this technique emulates some of the fastest processes in atomic physics with some of the slowest, leading to a temporal magnification factor of up to 12 orders of magnitude. In these experiments, time-varying forces on neutral atoms in the ground state of a tunable optical trap emulate the electric fields of a pulsed laser acting on bound charged particles. We demonstrate the correspondence with ultrafast science by a sequence of experiments: nonlinear spectroscopy of a many-body bound state, control of the excitation spectrum by potential shaping, observation of sub-cycle unbinding dynamics during strong few-cycle pulses, and direct measurement of carrier-envelope phase dependence of the response to an ultrafast-equivalent pulse. These results establish cold-atom quantum simulation as a complementary tool for studying ultrafast dynamics.
超快电子动力学通常使用脉冲激光进行研究。在这里，我们展示了一种互补的实验方法：使用囚禁的超冷原子对超快动力学进行量子模拟。反直觉的是，这种技术使用最慢的原子来模拟原子物理中最快的一些过程，从而产生高达 12 个数量级的时间放大因子。在这些实验中，可调谐光阱中基态中性原子上随时间变化的力模拟了作用在束缚带电粒子上的脉冲激光的电场。我们通过一系列实验证明了与超快科学的对应关系：多体束缚态的非线性光谱、通过势成形控制激发谱、在强几周期脉冲期间观察亚周期解缚动力学，以及对超快速等效脉冲响应的载波包络相位依赖性的直接测量。这些结果确立了冷原子量子模拟作为研究超快动力学的互补工具。
