This paper has been prepared by the Symphony collaboration (University of Warsaw, Uniwersytet Jagielloński, DESY/CNR and ICFO) on the occasion of the 25th anniversary of the "simple man's models" which underlie most of the phenomena that occur when intense ultrashort laser pulses interact with matter. The phenomena in question include High-Harmonic Generation (HHG), Above-Threshold Ionization (ATI), and Non-Sequential Multielectron Ionization (NSMI). "Simple man's models"provide, both an intuitive basis for understanding the numerical solutions of the time-dependent Schr\"odinger equation, and the motivation for the powerful analytic approximations generally known as the Strong Field Approximation (SFA). In this paper we first review the SFA in the form developed by us in the last 25 years. In this approach SFA is a method to solve the TDSE, in which the non-perturbative interactions are described by including continuum-continuum interactions in a systematic perturbation-like theory. In this review we focus on recent applications of SFA to HHG, ATI and NSMI from multi-electron atoms and from multi-atom molecules. The main novel part of the presented theory concerns generalizations of SFA to: (i) time-dependent treatment of two-electron atoms, allowing for studies of an interplay between Electron Impact Ionization (EII) and Resonant Excitation with Subsequent Ionization (RESI); (ii) time-dependent treatment in the single active electron (SAE) approximation of "large" molecules and targets which are themselves undergoing dynamics during the HHG or ATI process. In particular, we formulate the general expressions for the case of arbitrary molecules, combining input from quantum chemistry and quantum dynamics. We formulate also theory of time-dependent separable molecular potentials to model analytically the dynamics of realistic electronic wave packets for molecules in strong laser fields. We dedicate this work to the memory of Bertrand Carré, who passed away in March 2018 at the age o.

中文翻译：

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强场近似交响曲

这篇论文是由 Symphony 合作（华沙大学、Uniwersytet Jagielloński、DESY/CNR 和 ICFO）在“简单人模型”25 周年之际编写的，该模型是强超短激光脉冲时发生的大多数现象的基础与物质相互作用。所讨论的现象包括高谐波产生 (HHG)、阈值以上电离 (ATI) 和非顺序多电子电离 (NSMI)。“简单人的模型”为理解与时间相关的 Schr\"odinger 方程的数值解提供了直观的基础，以及通常称为强场近似 (SFA) 的强大解析近似的动机。在本文中，我们首先以我们在过去 25 年中开发的形式审查 SFA。在这种方法中，SFA 是一种解决 TDSE 的方法，其中非微扰相互作用是通过在系统的类微扰理论中包含连续-连续相互作用来描述的。在这篇综述中，我们重点介绍了 SFA 在 HHG、ATI 和 NSMI 中来自多电子原子和多原子分子的最新应用。所提出理论的主要新颖部分涉及 SFA 对以下方面的概括：（i）双电子原子的时间相关处理，允许研究电子碰撞电离 (EII) 和共振激发与后续电离 (RESI) 之间的相互作用；(ii) 在 HHG 或 ATI 过程中自身经历动态变化的“大”分子和目标的单活性电子 (SAE) 近似中的时间依赖性处理。特别是，我们为任意分子的情况制定了一般表达式，结合了量子化学和量子动力学的输入。我们还制定了时间相关的可分离分子势理论，以分析模拟强激光场中分子的真实电子波包的动力学。我们将这部作品献给 Bertrand Carré，他于 2018 年 3 月去世，享年 o.