So just to clear things up before we start, does vacuum polarization occur randomly, or does it just occur when an electromagnetic field is present? Also, how would vacuum polarization conserve energy - does it take energy from the field or does it emit negative energy gravity waves or something? Also, in the process of Hawking radiation, what actually happens? Does it absorb an antiparticle and emit the other, or does it absorb one of the photons emitted after annihilation? Cheers guys.