In quantum physics, the
uncertainty principle implies that
the
vacuum is not absolute as this would contradict the uncertainty associated with both time and energy content. Instead, it is filled with particle/antiparticle pairs, e.g. an
electron combined with a
positron, with net zero energy. These pairs are annihilated within the Planck limit.
In the presence of a field, e.g. an
electromagnetic field around an electron, these particle-antiparticle pairs reposition themselves, thus partially counteracting the field (a partial screening effect). The field therefore will be weaker than would be expected when the vacuum would be completely empty.
This reorientation of the short-lived particle-antiparticle pairs is referred to as
vacuum polarization.
See also
Category:Quantum field theory