Li Xinwei, Ning Honglie, Mehio Omar, Zhao Hengdi, Lee Min-Cheol, Kim Kyungwan, Nakamura Fumihiko, Maeno Yoshiteru, Cao Gang, Hsieh David
Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA.
Department of Physics, California Institute of Technology, Pasadena, California 91125, USA.
Phys Rev Lett. 2022 May 6;128(18):187402. doi: 10.1103/PhysRevLett.128.187402.
The fate of a Mott insulator under strong low frequency optical driving conditions is a fundamental problem in quantum many-body dynamics. Using ultrafast broadband optical spectroscopy, we measured the transient electronic structure and charge dynamics of an off-resonantly pumped Mott insulator Ca_{2}RuO_{4}. We observe coherent bandwidth renormalization and nonlinear doublon-holon pair production occurring in rapid succession within a sub-100-fs pump pulse duration. By sweeping the electric field amplitude, we demonstrate continuous bandwidth tuning and a Keldysh crossover from a multiphoton absorption to quantum tunneling dominated pair production regime. Our results provide a procedure to control coherent and nonlinear heating processes in Mott insulators, facilitating the discovery of novel out-of-equilibrium phenomena in strongly correlated systems.
莫特绝缘体在强低频光驱动条件下的命运是量子多体动力学中的一个基本问题。利用超快宽带光谱技术，我们测量了非共振泵浦莫特绝缘体Ca₂RuO₄的瞬态电子结构和电荷动力学。我们观察到在小于100飞秒的泵浦脉冲持续时间内，相干带宽重整化和非线性双空穴-双电子对产生相继发生。通过扫描电场幅度，我们展示了连续的带宽调谐以及从多光子吸收到量子隧穿主导的对产生机制的凯尔迪什转变。我们的结果提供了一种控制莫特绝缘体中相干和非线性加热过程的方法，有助于在强关联系统中发现新型非平衡现象。
