You can get that from the compactness of U(1) though. Or from anomaly cancellation if you include gravity, I think. I'd say that, given the standard model, the case for GUTs is (1) a generation arises very naturally from an SU(5) or SO(10) multiplet (2) the near-unification of coupling constants...
Oops, I posted that a bit prematurely. Fortunately I'm almost done...
This is the last of Sabine Hossenfelder's 7 coincidences, and it may well be the most important discovery of the Large Hadron Collider.
The usual interpretation of the data concerning the Higgs is that it is a problem for...
I appreciate Sabine Hossenfelder's latest video, and thought I would assemble some references. There's a mix of particle physics and cosmology topics. In general, the coincidences mentioned are mainstream topics in cosmology, whereas the particle physics coincidences are not.
1) Proton/electron...
That particular paper may have gone nowhere, but the general theme of quantum deformations of string theory has had a revival in recent years. String theory had its start in some particle scattering formulas (Veneziano amplitude, Virasoro-Shapiro amplitude) which began life purely as algebraic...
George: With the right explanation, it wouldn't take five years, or even five days, to arrive at a clearer picture. But a lot depends on what you already understand. Which of these have you already heard about: the uncertainty principle, the superposition principle, path integrals...
After the news of Peter Higgs's death, I was thinking of the Higgs field and boson, how central they are to physics now, and the remaining mysteries associated with them.
One such is the meaning of the mass actually observed for the Higgs boson. In the mainstream of theoretical physics, the...
One of his more obscure honors is that in theoretical physics, he became a verb. The earliest reference I can find to being higgsed is from 1981, while higgsing had to wait until the 1990s, but it's now standard jargon for spontaneously breaking a symmetry.
In their paper they claim their theory can explain MOND, also why the cosmological constant is small but nonzero, and why the MOND acceleration constant is proportional to the square root of the cosmological constant.
Sabine Hossenfelder already rebutted the claim of obtaining MOND. The...
The bridge between quantum field theory and a classical field state is something called a coherent state. Essentially, a coherent state is a kind of quantum field state that resembles a classical field state.
So in quantum gravity one normally says that the classical metric is a coherent state...
I note the recent paper
"Generalized Symmetry in Dynamical Gravity" (Clifford Cheung et al)
which is unusual in being an advanced, technical, mainstream work of quantum field theory, in which Ashtekar variables are used at one point. But note, they are not proposing a fundamental theory of...
I meant reference 3.
It's been noted here for many years that in Carl Brannen's eigenvalue formulation of the Koide formula, the mass scale is determined by a quantity equal to the mass of a "constituent quark", i.e. a quark in the context of a nucleon, dressed with whatever extra stuff is...
This thread was launched by the idea of a "waterfall" of Koide-like relations that relate the masses of all the quarks as well as the charged leptons. An esoteric idea buried in that paper (in part 3), is that the more fundamental version of this "waterfall" starts with a massless up quark, but...
A comment on @Vanadium 50 #21.
Certainly the path to the actual hydrogen atom via string theory requires first finding a string vacuum (if there is one) in which all the particles have the right masses, etc, then building a proton out of quarks (the Sakai-Sugimoto model gives us an idea of how...
We could try :-) If I was doing it, I'd just try to imitate a field-theory model of the hydrogen atom using stringy ingredients. E.g. model an electron bound to a proton, as a light string bound to a heavy D0-brane.