Ultrafast optical manipulation of ordered phases in strongly correlated materials is a topic of significant theoretical, experimental, and technological interest. Inspired by a recent experiment on light-induced superconductivity in fullerenes [M. Mitrano et al., Nature (London) 530, 461 (2016)], we develop a comprehensive theory of light-induced superconductivity in driven electron-phonon systems with lattice nonlinearities. In analogy with the operation of parametric amplifiers, we show how the interplay between the external drive and lattice nonlinearities lead to significantly enhanced effective electron-phonon couplings. We provide a detailed and unbiased study of the nonequilibrium dynamics of the driven system using the real-time Green's function technique. To this end, we develop a Floquet generalization of the Migdal-Eliashberg theory and derive a numerically tractable set of quantum Floquet-Boltzmann kinetic equations for the coupled electron-phonon system. We study the role of parametric phonon generation and electronic heating in destroying the transient superconducting state. Finally, we predict the transient formation of electronic Floquet bands in time- and angle-resolved photoemission spectroscopy experiments as a consequence of the proposed mechanism.

中文翻译：

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参数放大电子声子超导理论

在高度相关的材料中对有序相进行超快速光学处理是一个重要的理论，实验和技术热点。受富勒烯中光诱导的超导性最近实验的启发[M. Mitrano 等。，自然（伦敦） 530，461（2016）]，我们开发了具有晶格非线性的驱动电子-声子系统中光诱导的超导性的综合理论。与参数放大器的操作类似，我们展示了外部驱动和晶格非线性之间的相互作用如何导致有效增强的电子-声子耦合。我们使用实时格林函数技术对被驱动系统的非平衡动力学进行了详尽而公正的研究。为此，我们开发了Migdal-Eliashberg理论的Floquet泛化，并导出了耦合电子-声子系统的量子Floquet-Boltzmann动力学方程的数值可处理集合。我们研究了参数声子产生和电子加热在破坏瞬态超导状态中的作用。最后，