Laser-produced electron–positron pair production has been under discussion in the literature since 1969. Large numbers of positrons have been generated by lasers for a few years in studies which are also related to the studies of the physics of the fast ignitor laser fusion concept. For electron–positron pair production in vacuum due to vacuum polarization as predicted by Heisenberg (1934) with electrostatic fields, high-frequency laser fields with intensities around 1028 W/cm2 are necessary and may be available within a number of years. A similar electron acceleration by gravitation near black holes denoted as Hawking–Unruh radiation was discussed in 1985 by McDonald. The conditions are considered in view of the earlier work on pair production, change of statistics for electrons in relativistic black body radiation, and an Einstein recoil mechanism with a consequence of a physical foundation of the fine structure constant.