标题： 利用光驱动集体电流激发：两时间$GW$方法 显示英文标题

标题： Driving collective current excitations using light: The two-time $GW$ approach

摘要： 我们识别出一种独特的横向集体激发，我们称之为“curron”，它来源于驱动量子金属中的电流-电流相互作用。与涉及纵向电荷振荡的等离子体不同，curron 是由电流产生的矢量势与外部驱动场之间的相互作用引起的横向电流密度振荡。我们通过在非平衡双时间（TT）$GW$形式下在复时间路径上求解 Kadanoff-Baym 方程，在钠金属中展示了这种激发的出现，据我们所知，这是在真实材料上进行的首次 TT-$GW$计算。我们进一步表明，双时间量子记忆效应留下可测量的特征：泵浦引起的电流-场响应基线升高，可能在偏振和动量分辨的电导实验中观察到。通过从 TT-$GW$动力学中提取有效的电阻和记忆系数，我们引入了一种广义的 d'Alembert 波方程，该方程捕捉了驱动量子系统固有的多体阻尼和滞后效应。这些结果确立了电流-电流响应函数作为在关联物质中利用定性新集体动力学的平台，为超越电荷密度动力学探测光-物质相互作用开辟了新的途径。 显示英文摘要

摘要： We identify a distinct transverse collective excitation, which we name the "curron", arising from current-current interactions in a driven quantum metal. Unlike plasmons, which involve longitudinal charge oscillations, currons are transverse current-density oscillations resulting from the interplay between the vector potential generated by the current and the external driving field. We demonstrate the emergence of this excitation in sodium metal by solving the Kadanoff-Baym equations on a complex time contour within the non-equilibrium two-time (TT) $GW$ formalism, marking, to our knowledge, the first TT-$GW$ calculation on a realistic material. We further show that two-time quantum memory effects leave measurable signatures: a pump-induced elevation in the baseline of the current-to-field response, potentially observable in polarization- and momentum-resolved conductivity experiments. By extracting effective resistive and memory coefficients from the TT-$GW$ dynamics, we introduce a generalized d'Alembert wave equation that captures the many-body damping and retardation inherent to driven quantum systems. These results establish current-current response functions as a platform to harness qualitatively new collective dynamics in correlated matter, opening new avenues for probing light-matter interactions beyond charge-density dynamics.