Quantum electrodynamics predicts that the quantum vacuum is birefringent, but due to very small cross-section this yet be confirmed by experiment. Vacuum birefringence arises as elastic part of photon-photon scattering; inelastic Breit-Wheeler pair-production. We outline how measurements photon-polarised nonlinear process can used infer a measurement birefringence. As an example scenario, we ca...

In this article, we use the general theory derived in Paper I [M. Tacu and D. Bénisti, Phys. Plasmas 29, 052108 (2022)] order to address several long-standing issues regarding nonlinear electron plasma waves (EPWs). First, discuss relevance practical usefulness of stationary solutions Vlasov–Poisson system, so-called Bernstein–Greene–Kruskal modes, model slowly varying waves. Second, derive an ...