Speaker
Dr
Felix Karbstein
Description
The photon polarization tensor is the central object in an effective theory describing photon propagation in the quantum vacuum. It accounts for the vacuum fluctuations of the underlying theory, and in the presence of external electromagnetic fields, gives rise to such striking phenomena as vacuum birefringence and dichroism. For homogeneous magnetic fields it is explicitly known at one-loop accuracy in momentum space. Most of the studies currently available are manifestly carried out in momentum space, and are often limited to both constant fields and on-the-light-cone dynamics. We aim at insights into the photon polarization tensor beyond this restrictions: We emphasize that the full momentum dependence is essential in the treatment of problems explicitly posed in position space. Moreover, we argue that considerations of this type can provide access to new phenomena, such as quantum reflection of probe photons off the
polarized quantum vacuum.
