
Coma Berenices
The unification of interactions

A dream of Physics, which seems largely unjustified, has always been the unification of the four fundamental interactions.
that is to say the formation of a uniform mathematical form, capable of describing the total and each interaction separately, as a special case. As much as this may seem bold, it has a precedent. While magnetism and electricity are different phenomena on the surface, they constitute one and only interaction; and they are described with absolute accuracy by four equations, the elegant Maxwell equations of electromagnetism.

In seeking to unify the interactions Einstein himself spent much of his life; and this unification has no justification or aim, other than the belief in the deeper symmetry and simplicity of the natural world. It is therefore noteworthy that particularly in recent years the attempt to unify the interactions has already shown impressive progress.

First and foremost, the mechanism of the interactions seems to be common, since it is essentially based on the exchange of a "carrier" among the elementary particles. The properties of this carrier, which sometimes has mass or load and sometimes not, give each interaction its distinct character. This happens, however, as long as the energies of the particles are those of the current Universe; in higher energies the carriers of the interactions will start simulating each other. Then the interactions acquire the same force and can be described with the same mathematical language. (...)



Persistent theoretical searches soon led to the formulation of the Grand Unified Theories. (...) What remained was an obvious direction. The Grand Unified Theories expanded, in terms of their applications, to the conditions prevailing during the first split second after the Big Bang. It was exactly then when the energy of the "experiment" for the creation of the Universe was the one required by the theory for the unification of at least the three interactions.



