Quantum vacuum nonlinearities in the all-optical regime

光的非线性自相互作用是量子真空复杂性质的直接表现。在第二个资助期内，本项目研究聚焦激光场诱导的特定自相互作用现象对量子真空的非线性性质的影响。在第二个资助期内，本项目研究了量子真空的非线性性质对特定自相互作用现象的影响。基于宏观可控的超强激光脉冲，我们希望能够找到一种足够简单有效的实验结构来发现这些现象，并对其进行全面的描述，这就需要对真实激光脉冲中的虚拟量子过程以及在时空中动态诱导的特征进行定量处理。该项目使用并进一步发展有效的场论方法，研究强场环境中量子电动力学（QED）的一般光子观测值，并旨在从第一原理和此类实验的充分建模中进行准确预测。此外，还将利用现代重整化流技术解决与光-物质相互作用量子场论的高强度极限有关的概念问题。在方法方面，这涉及高性能使用和进一步发展第一个资助期开创的数值和模拟方法，对于所需现象的定量准确描述以及经典背景的建模。在概念方面，该项目进一步探索QED在最高强度下的结构性质和一致性。

Nonlinear self-interactions of light are a direct manifestation of the intricate properties of the quantum vacuum. They represent a demarcation from Maxwell's classical theory of the electromagnetic field, violating the superposition principle as a fundamental property of the classical vacuum.In the second funding period, this project investigates the consequences of the nonlinear nature of the quantum vacuum for specific self-interaction phenomena induced by focused laser fields. The goal is the identification and a comprehensive description of sufficiently simple and efficient experimental configurations that can serve as discovery experiments of these phenomena based on macroscopically controllable ultra-intense laser pulses.For this, the challenge of a quantitative treatment of virtual quantum processes in realistic laser pulses and the induced signatures dynamically in space and time has to be met. The project uses and further develops effective field theory methods, investigates general photonic observables of quantum electrodynamics (QED) in strong-field environments, and aims at accurate predictions from first principles and an adequate modeling of such experiments. Also questions of conceptual relevance for the high-intensity limit of the quantum field theory of light-matter interactions shall be addressed using modern renormalization flow techniques.On the method side, this involves the high-performance use and further development of numerical and simulational approaches, pioneered in the first funding period, for a quantitatively accurate description of the desired phenomena as well as a modeling of the classical background. On the conceptual side, the project further explores the structuralproperties and consistency of QED at highest intensities.