High Quality Content by WIKIPEDIA articles! In quantum field theory, and specifically quantum electrodynamics, vacuum polarization describes a process in which a background electromagnetic field produces virtual electron–positron pairs that change the distribution of charges and currents that generated the original electromagnetic field. It is also sometimes referred to as the self energy of the gauge boson (photon). Vacuum polarization was observed experimentally in 1997 using the TRISTAN particle accelerator in Japan.