Dynamical Schwinger effect and high-intensity lasers. Realising nonperturbative QED

We consider the possibility of experimental verification of vacuum e⁺e^- pair creation at the focus of two counter-propagating optical laser beams with intensities 10²⁰–10$^{22}~{\rm W/cm}^2$, achievable with present-day petawatt lasers, and approaching the Schwinger limit: 10$^{29}~{\rm W/cm}^2$ to be reached at ELI. Our approach is based on the collisionless kinetic equation for the evolution of the e⁺ and e^- distribution functions governed by a non-Markovian source term for pair production. As possible experimental signals of vacuum pair production we consider e⁺e^- annihilation into γ-pairs and the refraction of a high-frequency probe laser beam by the produced e⁺e^- plasma. We discuss the dependence of the dynamical pair production process on laser wavelength, with special emphasis on applications in the X-ray domain (X-FEL), as well as the prospects for μ⁺μ^- and π⁺π^- pair creation at high-intensity lasers. We investigate perspectives for using high-intensity lasers as "boosters" of ion beams in the few-GeV per nucleon range, which is relevant, e.g., to the exploration of the QCD phase transition in laboratory experiments.