The photon polarization tensor in a homogeneous magnetic or electric field

Understand

We revisit the photon polarization tensor in a homogeneous external magnetic or electric field.

• The starting point of our considerations is the momentum space representation of the one-loop photon polarization tensor in the presence of a homogeneous electromagnetic field, known in terms of a double parameter integral.
• Our focus is on explicit analytical insights for both on- and off-the-light-cone dynamics in a wide range of well-specified physical parameter regimes, ranging from the perturbative to the manifestly nonperturbative strong field regime.
• The basic ideas underlying well-established approximations to the photon polarization tensor are carefully examined and critically reviewed.