标题： 光激发超导体中的啁啾振幅模式 显示英文标题

标题： Chirped amplitude mode in photo-excited superconductors

摘要： 使用最先进的数值方法，我们展示了当考虑涨落时，希格斯模式在激发不足的情况下表现出啁啾振荡和指数衰减。 这与传统的无碰撞BCS动力学形成鲜明对比，后者预测的是幂律衰减和不存在啁啾现象。 这种具有啁啾幅度的模式使我们能够在系统处于长寿命预热态时确定有效势能的局部变化。 随后，我们证明了这种啁啾幅度模式是可以被实验观测到的量，因为在泵浦-探测实验中的光诱导（超）电流可以作为序参量动力学的有效代理，包括啁啾动力学。 我们的结果基于吸引性的 哈伯德模型，在超导能隙激发后处于对称破缺态的动力平均场理论。 由于集体响应涉及长时间尺度，我们将非平衡格林函数的层次低秩压缩方法扩展到对称破缺态，并证明尽管存在长时间记忆核，它仍能作为一种有效的表示方法。 显示英文摘要

摘要： Using a state-of-the-art numerical scheme, we show that the Higgs mode under excitation exhibits chirped oscillations and exponential decay when fluctuations are included. This is in stark contrast to conventional BCS collisionless dynamics which predict power-law decay and the absence of chirping. The chirped amplitude mode enables us to determine the local modification of the effective potential even when the system is in a long-lived prethermal state. We then show that this chirped amplitude mode is an experimentally observable quantity since the photoinduced (super)current in pump-probe experiments serves as an efficient proxy for the order parameter dynamics, including the chirped dynamics. Our result is based on the attractive Hubbard model using dynamical mean-field theory within the symmetry-broken state after a excitation across the superconducting gap. Since the collective response involves long timescales, we extend the hierarchical low-rank compression method for nonequilibrium Green's functions to symmetry-broken states and show that it serves as an efficient representation despite long-lived memory kernels.