Uehling potential

The vacuum (light blue) acts as a polarizable medium (composed of virtual particle-antiparticle pairs) that slightly modify the electric potential of the electron (depicted in the middle with minus sign).

In quantum electrodynamics, the Uehling potential describes the interaction potential between two electric charges which, in addition to the classical Coulomb potential, contains an extra term responsible for the electric polarization of the vacuum. This potential was found by Edwin Albrecht Uehling in 1935.[1][2]

Uehling's corrections take into account that the electromagnetic field of a point charge does not act instantaneously at a distance, but rather it is an interaction that takes place via exchange particles, the photons. In quantum field theory, due to the uncertainty principle between energy and time, a single photon can briefly form a virtual particle-antiparticle pair, that influences the point charge. This effect is called vacuum polarization, because it makes the vacuum appear like a polarizable medium. By far the dominant contribution comes from the lightest charged elementary particle, the electron. The corrections by Uehling are negligible in everyday practice, but it allows to calculate the spectral lines of hydrogen-like atoms with high precision.

  1. ^ Uehling, E. A. (1935). "Polarization Effects in the Positron Theory". Physical Review. 48 (1): 55–63. Bibcode:1935PhRv...48...55U. doi:10.1103/physrev.48.55.
  2. ^ Schwartz, M. D. (2013). "16". Quantum Field Theory and the Standard Model. Cambridge University Press. ISBN 978-1-107-03473-0.