Probing the non-perturbative regime of Quantum Electrodynamics with extreme light

Objective

The NP-QED project aims at testing the predictions of Quantum Electrodynamics (QED) – the theory of light matter interactions – in yet unexplored, extreme regimes. The first of these is the strong-field regime of QED, which begins when light amplitude hits the threshold of vacuum breakdown, occurring at the Schwinger field limit ~1018V/m. At this threshold, it is predicted that a light beam can deflect another light beam in a vacuum – violating Maxwell’s equations- and even generate electron positron pairs from the vacuum itself. Due to the huge field strengths required, SF-QED predictions have never been tested in a laboratory. Pushing three orders of magnitude beyond the Schwinger limit, the second regime explored by this project is the fully non-perturbative regime of QED. This is a completely uncharted area where current theoretical approaches are expected to fail, making it an active frontier of discovery for contemporary physics. Leveraging breakthrough innovations from our teams in areas such as laser intensity boosting using plasma mirrors, compact laser-plasma electron accelerators, particle detection techniques, exascale modelling and SF-QED theory, we will synergistically design, implement, and analyze a whole new class of experiments dedicated to probe the strong field and fully non-perturbative regimes of QED in the laboratory. These experiments will collide an ultra-short and relativistic electron beam generated by a laser-plasma accelerator with a high-power femtosecond laser strongly amplified using a plasma mirror optical component. Conducted at upcoming flagship European multi-Petawatt laser and accelerator facilities, this setup should achieve field strengths up to 1,000 times the Schwinger limit in the electrons’ rest frame. These first-of-their-kind experiments shall both validate long-standing SF-QED predictions and drive the development of new theoretical frameworks as we approach the fully non-perturbative regime.