Wow. I hadn't read this. Does this force have a name & an accessible explanation of how it degrades to 3 separate forces at low energies?
In particular, electromagnetism (EM) and the weak force (WF) are represented mostly by the U(1) group and SU(2) groups, respectively.
In pure electromagnetism, U(1)_em is what we're observing. This group is linked to a field caused by electric charge.
But if we drill into it, there is also and underlying U(1)_y, that is linked to a hypercharge that is a combination of of electric charge and the WF interaction strength.
The physics of the combined electroweak force is defined by the combined gauge group:
SU(2)_L x U(1)_y
From this fundamental physics we get (as energies get low enough) the Higgs mechanism through "spontaneous symmetry breaking".
This causes two new independent fields from a linear combination of the fields associated with the two above gauge symmetries. One of this gives rise to observable photons, and one gives rise to observable (kind of) W, Z+ and Z-.
And also quite significantly, this mechanism also gives rise to the Higgs field itself, which in turn provides mass (inertia). Without the Higgs mechanism, the particles arising from "pure" U(1) and SU(2) fields would be massless.
What I understood, while reading this part of the article, was the author meant something along the line of supersymmetry[1,2] (as Groups are all about symmetry – up to isomorphism).
From CERN Supersymmetry article[1]:
If supersymmetric particles were included in the Standard Model, the interactions of its three forces – electromagnetism and the strong and weak nuclear forces – could have the exact same strength at very high energies, as in the early universe.
> the forces that hold atomic nuclei together
Isn't that the strong nuclear force which isn't unified with electroweak according to wikipedia? Ah [1] suggests that maybe Wikipedia just hasn't caught up and the math suggests that the strong nuclear force and even gravity may all be unified into a single such force. That's supremely fascinating.
[1] https://www.symmetrymagazine.org/article/what-is-the-electro...
My understanding is that the “electroweak unification” (electromagnetism + weak force) is considered experimentally confirmed, whereas the “grand unification” (electroweak + strong force) is something most physicists believe to be possible but the theories remain somewhat speculative. For instance, if true, such unification likely means that the proton should be an unstable particle that very slowly decays, and that has never been observed experimentally.
Unifying such a “grand unified theory” with gravity (general relativity) is however a much harder problem: While all the other forces are already understood in terms of quantum mechanics, gravity is currently understood in terms of geometry, and it’s not obvious how to combine those in a sane way. That’s where string theory, quantum loop gravity, etc, come in; but AFAIK, most prospective theories are very far from even experimental predictions, let alone experimental testing, and not everyone even agrees on the premise that gravity “should” be described using quantum field theory.
We just know that our current theories can’t be complete, since thought experiments like “what is gravity during a quantum double slit experiment” or “what really happens near and inside a black hole” can’t be answered in a fully satisfactory way using current theories.