Polarization tensors in a strong magnetic field

Abstract

The vacuum polarization tensor in strong external magnetic fields has been evaluated numerically for various strengths of magnetic fields and momenta of photons under the threshold of the $e^{\pm }$ pair creation. The fitting formula has been obtained which reproduces the calculated results within 10 % of error. The proper time method is employed further to obtain the retarded polarization tensor for finite temperature plasmas.

Comments: 16 pages, using REVTeX and 5 postscript figures