This blog is not primarily a theory development blog. I report new scientific developments from credible or notable sources and I comment on those developments.
But, I would be an empty head indeed if I didn't draw some conclusions from many years of reporting hundreds of new developments a year and reviewing far more papers that I don't comment upon because they add little to the discussion or concern topics that are beyond my usual areas of interest.
I don't devote a lot of effort to touting my personal theories because I'm just a guy who majored in math, took almost enough classes to have a physics major as an undergraduate, and who reads lots of educated layman oriented books and reads lots of original physics research papers. In short, I'm not an expert in the field and my personal opinion doesn't matter much.
But, neo asked about my views in comments to another post, however, and I answered, so I'm posting this exchange in a place a little more prominent as a sort of full disclosure so that readers can discern my biases. Overall, I am very skeptical of many popular extensions to the Standard Model, although I do have some ideas about "within the Standard Model" explanations of its constants, cosmology, and quantum gravity that are not majority views among scientists.
neo said...whats ur fav extension of the SM to explain the remaining mysteries? June 19, 2018 at 9:39 PM
andrew said...Dirac neutrinos which receive mass in a manner similar to the Higgs mechanism, and quantum gravity effects that explain dark matter and dark gravity a la A. Deur with a single massless graviton.
The aggregate mass of the fundamental particles squared is equal to Higgs vev squared, and a Koide-like relationship between the fermion masses that arises dynamically via W boson exchanges. June 19, 2018 at 9:47 PM
andrew said...
andrew said...Also, once quantum gravity is merged with the SM that changes the running of all of the SM constants subtly, and I think it is quite likely that this subtle tweak will lead to gauge unification.
Quantum gravity effects will explain the impossible early galaxy problem and the 21cm result that is consistent with there not being any dark matter.
Other than the graviton, I do not think that there are going to be any non-SM particles of any kind other than possibly more fundamental particles that can only give rise to SM particles and a massless graviton.
I do not think that any fundamental forces other than the three of the SM and graviton carried by a massless graviton will be discovered.
I am not strongly committed to the concept that the universe is either strictly causal or strictly local. I am agnostic about whether space-time comes in quanta or is continuous.
I think that the baryon asymmetry of the universe arises from another universe on the other side of the Big Bang in the time dimension, in which the second law of thermodynamics has the opposite direction.
I think that cosmological inflation is at best unprovable and is quite likely wrong. June 19, 2018 at 10:00 PM
andrew said...I think it is plausible that there is a maximal mass-energy density and that this gives rise to asymptotic safety in gravity.
I think that gravitational energy is conserved and can be localized.
I think that there are no primordial black holes, and that any wormholes are not sufficiently large to transfer anything macroscopic.
I think that the muon g-2 discrepancy is due to a combination of experimental and theoretical error and will disappear, as will evidence for non-PMNS model neutrino oscillations such as sterile neutrinos, and evidence for violations of lepton universality of the kind purportedly seen in B meson decays.
I think Koide's rule for chaged leptons will hold up to at least the ratio of neutrino mass to charged lepton mass level of precision.
I think that some variant of Koide's rule will fit the relative masses of the charged leptons. I think that the lightest neutrino mass eigenstate is on the order of 1 meV or less and that it has a non-zero mass and that there is a normal mass hierarchy for neutrinos.
I don't have a strong intuition regarding the ratio of neutrinos to antineutrinos in our universe as a whole.
It isn't implausible that some version of quark-lepton complementarity could prove to be correct.
I think that baryon number and lepton number are separately conserved except in sphaleron interactions, and I wouldn't be surprised if sphaleron interactions are found not to exist at all if we could ever generate of means to test that hypothesis. I'm not quite sure what the Noether's theorem implications are of that fact. There are no flavor changing neutral currents, no neutrinoless beta decay and there is no proton decay.
I think that we may be missing a rule or two in QCD that is critical to understanding the spectrum of scalar and axial vector hadrons. I would not be surprised if one of those rules has the effect of prohibiting glue balls. I think that all true hadrons with more than three valence quarks will prove to be wildly unstable although somewhat less unstable "hadron molecules" might be a thing. I think it isn't implausible that we could discover top quark hadrons that are extremely rare except at extremely high energies that are very short lived.
I expect that there are deep reasons for the gravity equals QCD squared coincidences that we observe. June 19, 2018 at 10:21 PM
neo said...no mention of string theory? personally i'm skeptical of both susy and extra dimensions.
regarding space time i've wondered why if QM has a wave particle duality, space and time couldn't also be both continuous and respect lorentz invariance, and discrete to explain BH entropy. it's a contentious-discrete duality June 20, 2018 at 8:31 AM
andrew said...I do not think that there are an integer number of extra dimensions. It isn't entirely implausible to me that the four dimensions of space-time that we observe are emergent rather than fundamental (as is common in loop quantum gravity-like quantum gravity theories), and/or that the dimensionality of space-time could be a fractal quantity that is non-integer (something also suggested by some descriptions of quantum mechanics).
I think mainstream SUSY with sparticals and extra Higgs bosons is almost surely wrong, but the particular balance of Standard Model constants that exists may reflect some fermion-boson symmetry in nature, because the sum of the square of the masses of the fundamental bosons is very close to the sum of the square of the masses of the fundamental fermions, and these sums may actually be equal at some appropriate running of those masses with energy scale (e.g. perhaps at the Higgs vev scale).
I have no opinion on a continuous-discrete space-time duality. June 20, 2018 at 1:08 PM
andrew said...String theory/M Theory may have some concepts that have some place in a final theory.But, it has gone far afield, is amorphous, and its commitment to pursue versions of string theory that reflect bad hypotheses like SUSY, Majorana neutrinos, dark matter particle theories, quintessence based dark energy theories, and a commitment to allowing baryon and lepton number violation in pursuit of a pure energy Big Bang, have led investigators in the field to explore corners of it that are particularly unfruitful. June 20, 2018 at 1:13 PM
neo said...I have no opinion on a continuous-discrete space-time duality.interesting,i'm not aware of any extensive literature on this .duality i'm proposing, just an observation that
1- nature seemingly respects lorentz invariance to a very high degree implying spacetime is continuous
2- black hole entropy seemingly implies spacetime is discrete
based on current LHC and other results I'm inclined to agree with you on string theory. obviously data can change this.
i've learned on physics forums urs scheiber and mitchell porter aren't fans of loop quantum gravity and even regard it is unphysical and an error since gravity is universal, i'm enchanted with ideas that gravity is a byproduct of QM, or that QM can be extended to give rise to gravity like phenomena June 20, 2018 at 4:33 PMSome notes:
* Links are to posts at this blog and/or outside links that are representative of ideas and are not necessarily comprehensive, definitive or best links to the concept.
* "dark gravity" This is a typo, I meant "dark energy".
* "I think that some variant of Koide's rule will fit the relative masses of the charged leptons." I meant "charged fermions".
2 comments:
hehe thanks
kinda neat to see this.
i guess the final question to round this all out,
what is ur fav QG theory? i.e QG theory most promising?
string/M-theory, LQG, AS, entropic gravity a la verlinde, etc?
since LHC hasn't found evidence of SUSY or extra dimensions, i think QG in 4D and no-SUSY are more promising than the leading contender string/M-theory
LHC null results on SUSY/KK states has no effect on Urs Scheiber and Mitchell Porter's support of string theory and dismissal of LQG.
personally I like the idea of extending QM to include effects that give rise to gravity, an example of this is Antoine Tilloy Ghirardi-Rimini-Weber model with massive flashes
"what is ur fav QG theory? i.e QG theory most promising? string/M-theory, LQG, AS, entropic gravity a la verlinde, etc?"
I think Alexander Deur's model of self-interacting gravitons which purports to be just standard GR but isn't, is the most promising by far but needs a collaboration with people more equipped to do the relativistic math and analyze the astronomy data and test it and replicate it to confirm that it works. I think I could assemble a hand picked collaboration to do that with about $1.5 million. But, I don't have $1.5 million.
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