The reality of vacuum polarization was mathematically established by Dirac in October of 1934. However, as late as September 1946, the question was still being asked whether this polarization of the vacuum can be measured. The answer came at the Shelter Island Conference the morning of June 2, 1947. It was delivered by Willis Eugene Lamb ( 1913-2008 ) 1955 Nobel Prize recipient on the shift of hydrogen’s energy levels as results of the electromagnetic interaction of the vacuum with its single orbital electron and single proton nucleus. Unfortunately, the answer was given by the opposite sign and 40 times larger than the value predicted earlier by Dirac. Till his death in 1984, Dirac considered this as one of the few disturbing theoretical failures of his life. Although the Lamb shift and the Casimir effect established conclusively the existence of vacuum polarizations and fluctuations of the quantized electromagnetic field, and this vacuum effect on electric charges gets stronger at shorter distances, on the contrary the vacuum polarization of quarks and gluons established asymptotic freedom and surprisingly, the vacuum effect on color charges gets weaker as shorter distances. These diametrically opposite effects of vacuum polarization for QED and QCD remain physically unsolved mysteries to this day.

Alternatively, if both quarks and electrons are composite particles of space-time charges, their different structures provide clues to their vacuum interactions. Since electron is composed of 1 H-plus and 7 H-minuses it has 8 space-time vertices. Likewise, an up quark has 6 vertices, down quark 4 vertices. Since a proton is composed of 2 up quarks and 1 down quark, it has 16 vertices. That is giving 8-vertex interaction between electron and proton, while at most 2-vertex interaction between quarks. The vacuum-vacuum self-interaction is a 6-vertex interaction. Therefore, depending on the direction, 8-vertex interaction gains 2 space-time charges, while 2-vertex loses 4 space-time charges, vice versa. That is to say the quantum vacuum can only gain or lose 6 vertices per exchange interaction.