All-optical signatures of quantum vacuum > > nonlinearity and the Heisenberg-Euler effective action

by Dr Felix Karbstein (Universität Jena)

Monday 4 Dec 2017, 14:15 → 16:45 Europe/Berlin

3344 (TUM - Physics Department - Garching)

The quantum vacuum is characterized by the omnipresence of quantum fluctuations of the underlying theory's particle degrees of freedom (in QED: electrons/positrons and photons) in the form of virtual processes. As electromagnetic fields couple to charged particles, the fluctuations of these virtual particles can give rise to effective nonlinear interactions among electromagnetic fields. Being of a true quantum nature and having no tree-level analogue, these couplings are typically extremely tiny.
The planning and commissioning of various high-intensity laser facilities worldwide just now, suggests a particularly promising route towards the first verification of QED vacuum nonlinearity in a well-controlled laboratory experiment. Aiming at performing such a discovery experiment with state-of-the-art technology, all-optical signatures of QED vacuum nonlinearity seem most promising. This class of signatures encompasses vacuum fluctuation mediated interaction processes, where both the microscopic origin of the electromagnetic fields driving the effect and the signal itself are photons.
In this talk, we briefly discuss the emergence of the renowned Heisenberg-Euler effective action from the underlying microscopic theory of QED and employ it to study various theoretical proposals to study QED vacuum nonlinearities in experiment.