2. See T. D. Lee, Particle Physics and Introduction to Field Theory, Harwood, New York, 1981,
p. 184. In particle physics the dipole is a particle-antiparticle broken symmetry in its fierce
energy exchange with the active vacuum.
https://archive.org/details/particle-physics-and-introduction-to-field-theory-t.-d.-lee/page/173/mode/2up
Downloads\extracting_EM_from_vacuum.pdf