Is particle physics dead, dying, or just hard?
quantamagazine.org
quantamagazine.org
I measured the electron's vector coupling to the Z boson at SLAC in the late 1990s, and the answer from that measurement is: we don't know yet - and that's the point.
Thirty years later, the discrepancy between my experiment and LEP's hasn't been resolved.
It might be nothing. It might be the first whisper of dark matter or a new force. And the only way to find out is to build the next machine. That's not 'dead', that's science being hard.
My measurement is a thread that's been dangling for decades, waiting to be pulled.
But it is not just about making money: The entire field of radiation therapy for cancer exists and continues to improve because people figured out ways to control particle beams with extreme precision and in a much more economical way to study particle physics. Heck, commercial MRIs exist and continue to improve because physicists want cheaper, stronger magnets so they can build more powerful colliders. What if in the future you could do advanced screening quickly and without hassle at your GP's office instead of having to wait for an appointment (and possibly pay lots of money) at an imaging specialist center? And if they find something they could immediately nuke it without cutting you open? We're talking about the ultimate possibility of Star Trek level medbays here.
Let the physicists build the damn thing however they want and future society will be better off for sure. God knows what else they will figure out along the way, but it will definitely be better for the world than sinking another trillion dollars on wars in the middle east.
There is a lot of handwaving going on here to justify the incredibly cheap, mostly privately funded investments that launched the computer generation with the massively expensive, extremely gradual gains we are making now with particle accelerators. Part of it is that people just can't imagine how little was invested in R&D to get these stunning results, given how much we have to invest today to get much less impressive results, so they just assume that semiconductors could not have been invented without tens of billion dollars of research.
There is diminishing returns, just as a 90nm process is really all you need to get 90% of the benefits of computerization -- you can drive industrial automation just fine, all the military applications are fine, etc. But to go from a 90nm process to a 3nm process is an exponential increase in costs. In a lot of fields we are at that tail end where costs are incredibly high and gains are very low, and new fields will need to be discovered where there is low hanging fruit, and those fields will not require "tens of billions" of dollars to get that low hanging fruit.
Even with particle accelerators, SLAC cost $100 million to build and generated a massive bounty of discoveries, dwarfing the discoveries made at CERN.
To pretend that there is no such thing as a curve of diminishing returns, and to say that things have always been this way is to not paint an accurate picture of how science works. New fields are discovered, discoveries come quickly and cheaply, the field matures and discoveries become incremental and exponentially more expensive. That's how it works. For someone who is in a field on the tail end of that process, it's not good history to say "things have always been this way and have always cost this much".
No. These two cases are absurdly different, and you're even completely misunderstanding (or misrepresenting) the meaning of the "tens of billions of dollars" figure.
Microchips were an incremental improvement where the individual increments yielded utility far greater than the investment.
For particle physics, the problem is that the costs have exploded with the size of facilities to reach higher energies (the "tens of billions of dollars" is for one of them) but the results in scientific knowledge (let alone technological advances) have NOT. The early accelerators cost millions or tens of millions and revolutionized our undestanding of the universe. The latest ones cost billions and have confirmed a few things we already thought to be true.
> Let the physicists build the damn thing and future society will be better off for sure.
Absolutely not.
You should look up how modern EUV lithography was commercialised. This was essentially a big plasma physics puzzle. If ASML hadn't taken on a ridiculous gamble (financially on the same order of magnitude as a new collider, esp. for a single colpany) with the research, Moore's law would have died long ago and the entire tech industry would be affected. And there was zero proof that this was going to work beforehand.
Engineers not being able to fathom that by building this huge-ass and complicated machines to answer questions about the fundamentals of nature, other problems are solved or new things are invented that improve and change our life will never not be funny to me
A statement that certain needs some backing.
You might say that the statement you were replying to also needs some backing, but they did give some, although you believe it was incorrect.
It just seems that "absolutely not" goes against the conventional wisdom that knowledge for knowledge sake will lead to some greater return than was expended on getting that knowledge somewhere down the road which really is one of the main underlying ideas of Western Civilization since before Newton.
Absolutely not means future society will not be better off! That seems to be a big weird absurdly pompous and conceited statement to make unless you have a time machine, or at least a big mess of statistics that can show that scientific advances in physics for a significant amount of time has failed to provide a return value on existence, although I would think that does not rise to the promise of "absolutely not".
Yes, but we had hopes that it would lead to more. And had lead to more, something only known to be false in hindsight, who knows where that would have ended us up? What if it upended the standard model instead of reinforcing it?
> Absolutely not.
What are we supposed to do then? As humans, I mean. No one knows why we're here, what the universe really is like. We have some pretty good models that we know are wrong and we don't know what wonders the theoretical implications of any successor models might bring. That said, do we really need to motivate fundamental research into the nature of reality with a promise of technology?
I'm not arguing for mindlessly building bigger accelerators, and I don't think anyone is - there has to exist a solid line of reasoning to warrant the effort. And we might find that there are smarter ways of getting there for less effort - great! But if there isn't, discrediting the venue of particle accelerators due to their high upfront cost as well as historical results would be a mistake. We can afford it, and we don't know the future.
I'd not be so sure about that. Doing this research will probably allow us to answer "it works but we don't know exactly why" cases in things we use everyday (i.e. li-ion batteries). Plus, while the machines are getting bigger, the understood tech is getting smaller as the laws of physics allows.
If we are going to insist on "Absolutely not" path, we should start with proof-of-work crypto farms and AI datacenters which consume county or state equivalents of electricity and water resources for low quality slop.
> Absolutely not.
And what do YOU mean, "absolutely not"? You have no more say in what happens than anyone else unless you're high level politician, who would still be beholden to their constituents anyway.
And yet big science, like particle accelerators, STILL gets funding. There's plenty to go around. Sure, every once in a while a political imperative will "pull the plug" on something deemed wasteful or too expensive and maybe sometimes that's right. But we STILL have particle physics, we STILL send out pure science space missions, there are STILL mathematicians and theorists who are paid for their whole careers to study subject matter that has no remotely practical applications.
Not everything must have a straight-line monetary ROI.
That's the problem with cutting edge reaserch....you don't even know if you will ever needed it or if a trilion dollar industry is waiting for just a number to be born
If that's the case it seems like it might be shrewd for younger investors to buy into physics research on a 15-20 year timeline?
Where do you think that tax money comes from?
Apple and Nvidia are creating the economies that produce tax revenue at every step of the way.
Government has always been the backbone of basic science research - no one else can reasonably bear the risk and the advances are public domain.
I suppose the only solution is undeground science. Do enough progress in silence, dont disseminare the results, unless the superiority becomes so obvious that an armed resistance becomes unthinkable.
"Fundamental Research" may or may not pan out, but the things that happen along the way are often valuable... I don't think there's any practical applications related to generating Higgs Bosons, but it's interesting (at least for particle physicists) and there's a bunch of practical stuff you have to figure out to confirm them.
That practical work can often generate or motivate industrial progress that's generally useful. For example, LHC generates tons of data and advances the state of the art in data processing, transmission, and storage; that's useful even if you don't care about the particle work.
Porn seems to be sustainably self funding; no need for government stimulus.
Only because you haven't seen the plans for the Large Hardon Collider
So look at it this way. Let’s take a bunch of the smartest people alive, train them for decades, give them a month of Google money, and they’ll spend 30 years advancing engineering to probe the very fabric of reality. And everything they learn will be shared with the rest of humanity for free.
Sounds like a pretty good deal to me.
But just like that money is generated, it's also all spent.
So the actual hard part is deciding what not to spend money on so we can build some crazy physics machines with a blurry ROI instead.
Unpopular opinion: Google makes an insane amount of money, so they can afford this salary. The CERN (or whatever your favourite research institute is), on the other hand, is no money-printing machine.
Is it?
You are assuming cold fusion is possible. We don't know that. It might be one more step before we finally prove it is never possible.
You are also assuming that cold fusion is something this path of research will lead us to. However this might be a misstep that isn't helpful at all because it doesn't prove anything useful about the as yet unknown physical process that cold fusion needs.
We just don't know, and cannot know at this point.
Similar statements were already claimed about nuclear fission power plants in the 70s.
There are talks of a Muon collider, also there's a spallation source being built in Sweden(?) and also of an electron 'Higgs factory' (and while the LHC was built for the Higgs boson it is not a great source for it - it is built as a generic tool that could produce and see the Higgs)
1) we know what to do, but it is expensive
2) we don't know what to do exactly, but many more people involved can increase search speed, so just need more people
3) it is purely sequential problem, and therefore it takes a lot of time
While other natural sciences often suffer from an abundance of things that "merely" need to be documented, or where simulation capability is the limit, particle physics is mostly based on a theoretical framework from the middle of the 20th century that has mostly beth explored.
Getting ahead in particle physics comprises measuring many arcane numbers to as high precision as possible until something doesn't line up with existing theories or other measurements anymore. More people could help with brainstorming and measuring things that don't require humongous particle accelerators.
The existing measurements at CERN ruled out a lot of the "more natural" variants of string theory. Until now this insight has not lead to a big scientific breakthrough.
Everybody knows we are not there yet and how the final knowledge set will look like, if its even possible to cover it (ie are quarks the base layer or we can go deeper, much deeper all the way to planck scales? dynamics of singularities etc)
The Standard Model predicts a specific value for the weak mixing angle, which determines the electron's vector coupling. My measurement at SLAC, along with other SLD measurements, consistently preferred a slightly different value than what LEP (the European competitor experiment) found using a different technique.
The key word there is "different technique." SLD used a polarized beam of electrons — a completely novel approach at the time — which gave us direct access to the left-right asymmetry without needing to untangle final-state effects. LEP extracted the same parameter from b-quark forward-backward asymmetry. Two fundamentally different methods probing the same physics, with different systematic exposures, giving different answers.
Both experiments had good resolution. We spent enormous effort characterizing the systematics, and they're small compared to the statistical uncertainty. But the two most precise determinations of this parameter disagreed at roughly the 3-sigma level — and that disagreement has never been explained. The world average splits the difference, and the Standard Model prediction is consistent with that average, so you could say "the SM is fine" if you squint. But nobody knows why the two experiments don't agree with each other.
It could be an unidentified systematic error in one experiment. It could be that something beyond the Standard Model is subtly shifting one measurement and not the other. That ambiguity is exactly what makes it a "dangling thread" rather than a resolved question.
Come now.
Many of those models naturally include a dark matter candidate. I didn't mean to imply 'we found dark matter' — it's that the theories which could explain the discrepancy often come with one attached.
Back then, we thought our theory was more or less complete while having experimental data which disproved it (Michelson-Morley experiment, Mercury perihelion, I am sure there are others).
Right now, we know our theories are incomplete (since GR and QFT are incompatible) while having no experimental data which contradicts them.
Consider e.g. neutrino masses. We have plenty of experimental data indicating that neutrinos oscillate and therefore have mass. This poses a problem for the standard model (because there are problems unless the mass comes from the Higgs mechanism, but in the standard model neutrinos can't participate in the Higgs mechanism due to always being left-handed). But whenever we do experiments to attempt to verify one of the ways of fixing this problem -- are there separate right-handed neutrinos we didn't know about, or maybe instead the right-handed neutrinos were just antineutrinos all along? -- we turn up nothing.
This again? It's only true if you insist on sticking with the original form of Weinberg's "model of leptons" from 1967 [1], which was written when massless neutrinos were consistent with available experimental data. Adding quark-style (i.e. Dirac) neutrino mass terms to the Standard Model is a trivial exercise. If doing so offends some prejudice of yours that right-handed neutrino can not exist because they have no electric and weak charge (in which case you must really hate photons too, not to mention gravity) you can resort to a Majorana mass term [2] instead.
That question (are neutrinos Dirac or Majorana?) is not a "contradiction", it's an uncertainty caused by how difficult it is to experimentally rule out either option. It is most certainly not "a problem for the standard model".
[1] https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.19.1264
[2] https://en.wikipedia.org/wiki/Majorana_equation#Mass_term
Edit: Doing some quick searching seems to indicate that giving neutrinos a bare mass term would violate electroweak gauge invariance? I don't know enough to evaluate that claim, or TBH really even to understand it. But I believe that's what I was thinking of, so maybe you can say how true and/or pertinent that is.
Giving any standard model fermion a bare mass term would violate electroweak gauge invariance. That was one of the problems with Glashow's electroweak model from 1961 [1]: he had the right symmetry group, but all particles had to be massless in order not to break it. Weinberg's contribution was to combine Glashow's proposal with Higgs' mass generation mechanism. It is done exactly the same way for any electroweak fermion doublet (as long as you are happy with the default choice of Dirac mass terms for all of them), be it up quark and down quark or neutrino and electron.
[1] https://www2.physik.uni-muenchen.de/lehre/vorlesungen/sose_2...
But if that's correct then I'm confused what your objection is to what I said earlier. If a bare mass would violate electroweak gauge invariance, then instead the mass should come from the Higgs mechanism, but that has the problem of, where are all the right-handed neutrinos, then? Am I missing something here? If you can't just give the neutrinos a bare mass and call it a day (at least not w/o causing significant problems), but do in fact have to make a more significant modification like inventing sterile neutrinos or making them Majorana particles, I'd call that a "contradiction" rather than merely a "question", because no hypothesis so far is a good fit for all of what we see (searches for sterile neutrinos have come up empty, neutrinoless double beta decay remains undetected, and I assume nobody's ever observed violations of electroweak gauge invariance!). Or I guess there are more out-there hypotheses that are consistent with what we see in that they've yet to really be tested, but, y'know, nothing that's been really tested AFAIK.
That is not a trivial problem at all. It certainly has not been solved, and it's possible experiments will say "Both the current ideas are wrong."
The matrix you are thinking of is presumably the PMNS matrix [1]. It's equivalent to the CKM matrix for quarks [2]. The purpose of both is to parametrize the mismatch between flavor [3] and mass eigenstates, not "to account for neutrino masses" or "explain their origin".
As far as the standard model is concerned, neutrino masses and quark masses all originate from Yukawa couplings [4] with the Higgs field. Adding such terms to Weinberg's original model of leptons is very much a trivial exercise, and was done already well before there was solid evidence for non-zero neutrino masses.
> it's possible experiments will say "Both the current ideas are wrong."
Assuming that by "Both current ideas" you mean Dirac vs Majorana mass, those are the only available relativistic invariants. For both to be wrong, special relativity would have to be wrong. Hopefully I don't need to explain how extraordinarily unlikely that is.
[1] https://en.wikipedia.org/wiki/Pontecorvo%E2%80%93Maki%E2%80%...
[2] https://en.wikipedia.org/wiki/Cabibbo%E2%80%93Kobayashi%E2%8...
[3] https://en.wikipedia.org/wiki/Flavour_(particle_physics)
This is getting tiresome...
It really fits well with the OP comments. Nothing really contradicts the theory but there's no deeper theory beyond it. Another comment mentioned as "nightmare" of dark matter only have gravitational interaction with other matter. That would be very unsatisfying for physicists but wouldn't something that really disprove any given theory.
But this might be easier to read: https://www.space.com/astronomy/black-holes/did-astronomers-...
The following seem likely to me: (1) Consciousness exists, and is not an illusion that doesn't need explaining (a la Daniel Dennett), nor does it drop out of some magical part of physical theory we've somehow overlooked until now; (2) Mind-matter interactions do not exist, that is, purely physical phenomena can be perfectly explained by appeals to purely physical theories.
Such are the stakes of "naturalistic dualist" thinkers like David Chalmers. But if this is the case, it implies that the physics of matter and the physics of consciousness are orthogonal to each other. Much like it would be a nightmare to stipulate that dark matter is a purely gravitational interaction and that's that, it would be a nightmare to stipulate that consciousness and qualia arise noninteractionally from certain physical processes just because. And if there is at least one materially noninteracting orthogonal component to our universe, what if there are more that we can't even perceive?
"in the specific regime covering the particles and forces that make up human beings and their environments, we have good reason to think that all of the ingredients and their dynamics are understood to extremely high precision"[0]
Sean Carroll's own favorite topics (emergent gravity, and the many worlds interpretation) are also things that we don't have any clue about.
Yes there is stuff we can calculate to very high precision. Being able to calculate it, and understanding it, are not necessarily the same thing.
You'd expect that at the bottom, the smallest objects would be extremely simple and would follow some single physical law.
But the smallest objects we know of still have pretty complex behavior! So there's probably another layer underneath that we don't know about yet, maybe more than one.
For a historical analogy, classical physics was and is sufficient for most practical purposes, and we didn't need relativity or quantum mechanics until we had instruments that could manipulate them, or that at least experienced them. While I guess that there were still macroscopic quantum phenomena, perhaps they could have just been treated as empirical material properties without a systematic universal theory accounting for them, when instruments would not have been precise enough to explore and exploit predictions of a systematic theory.
That presupposes that there's a bottom, and that each subsequent layer gets simpler. Neither proposition is guaranteed, indeed the latter seems incorrect since quantum chromodynamics governing the internal structure of the proton is much more complex than the interactions governing its external behavior.
Incompleteness is inherent to our understanding as the universe is too vast and endless for us to ever capture a holistic model of all the variables.
Gödel says something specific about human axiomatic systems, akin to a special relativity, but it generalizes to physical reality too. A written system is made physical writing it out, and never complete. Demonstrates that our grasp of physical systems themselves is always incomplete.
An environment living in Conway’s Game of Life could be quite capable of hypothesizing that it is implemented in Conway’s Game of Life.
Systems can hypothesize about themselves but they cannot determine why the rules they can learn exist in the first place. Prior states are no longer observable so there is always incomplete history.
Conway's Game of Life can't explain its own origins just itself. Because the origins are no longer observable after they occur.
What are the origins of our universe? We can only guess without the specificity of direct observation. Understanding is incomplete with only simulation and theory.
So the comment is right. We would expect to be able to define what is now but not completely know what came before.
We are finding local maximums(induction) but the establishment cannot handle deduction.
Everything is an overly complex bandaid. At some point someone will find something elegant that can predict 70% as good, and at some point we will realize: 'Oh that's great, the sun is actually at the center of the solar system, Copernicious was slightly wrong thinking planets make circular rotations. We just needed to use ellipses!'
But with particles.
This sounds like a distinction without consequence, but I think that's wrong. The sun is not special. It just has a lot of mass. If somebody learns: The earth orbits the sun-- They don't understand how two black holes can orbit each other. If somebody learns: The sun and the earth orbit their CM -- They will be able to understand that.
The point being it's not at all clear what we might be missing without these impractical little mysteries that so far are very distant from every day life.
There isn't even a general physical theory of window glass -- i.e. of how to resolve the Kauzmann paradox and define the nature of the glass transition. Glass is one of man's oldest materials, and yet it's still not understood.
There's also, famously, no general theory for superconducting materials, so superconductors are found via alchemical trial-and-error processes. (Quite famously a couple of years ago, if you remember that circus.)
Solid-state physics has a lot of big holes.
There exists a huge number of fundamental quantities that should be calculated from the parameters of the "standard model", but we cannot compute them, we can only measure them experimentally.
For instance, the masses and magnetic moments of the proton, of the neutron and of all other hadrons, the masses and magnetic moments of the nuclei, the energy spectra of nuclei, of atoms, of ions, of molecules, and so on.
The "standard model" can compute only things of negligible practical importance, like the statistical properties of the particle collisions that are performed at LHC.
It cannot compute anything of value for practical engineering. All semiconductor devices, lasers and any other devices where quantum physics matters are not designed using any consistent theory of quantum physics, but they are designed using models based on a great number of empirical parameters determined by measurement, for which quantum physics is only an inspiration for how the model should look like and not a base from which the model can be derived rigorously.
The fundamental laws of chemistry have not been changed much by quantum physics, they just became better understood and less mysterious. Quantum mechanics has explained various cases of unusual chemical bonds that appeared to contradict the simpler rules that were believed to be true before the development of quantum physics, but not much else has practical importance.
Solid-state physics is a much better example, because little of it existed before quantum physics.
Nevertheless, solid-state physics is also the most obvious example that the current quantum physics cannot be used to compute anything of practical value from first principles.
All solid-state physics is based on experimentally-measured parameters, which cannot be computed. All mathematical models that are used in solid-state physics are based on guesses about how the solutions could behave, e.g. by introducing various fictitious averaged potentials in equations, like the Schroedinger equation, and they are not based on computations that use primary laws, without guesses that do not have any other justification, except that when the model is completed with the experimentally-measured values for its parameters, it can make reasonably accurate predictions.
Using empirical mathematical models of semiconductor materials, e.g. for designing transistors, is perfectly fine and entire industries have been developed with such empirical models.
However, the fact that one must develop custom empirical models for every kind of application, instead of being able to derive them from what are believed to be the universal laws of quantum physics, demonstrates that these are not good enough.
We can live and progress very well with what we have, but if someone would discover a better theory or a mathematical strategy for obtaining solutions, that could be used to compute the parameters that we must now measure and which could be used to model everything that we need in a way for which there would be guarantees that the model is adequate, then that would be a great advance in physics.
The way we construct Hamiltonians is indeed somewhat ad hoc sometimes, but that’s not because of lack of fundamental knowledge. In fact, the only things you need are the mass of the electron/proton and the quantum of charge. Everything else is fully derived and justified, as far as I can think of. There’s really nothing other than the extremely low energy limit of QED in solid state devices, then it’s about scaling it up to many body systems which are computationally intractable but fully justified.
We don’t even use relativistic QM 95% of the time. Spin-orbit terms require it, but once you’ve derived the right coefficients (only needed once) you can drop the Dirac equation and go back to Schrödinger. The need for empirical models has nothing to do with fundamental physics, and all to do with the exorbitant complexity of many-body systems. We don’t use QFT and the standard model just because, as far as I can tell, the computation would never scale. Not really a fault of the standard model.
Um, false? The fundamentals of chemistry are about electron orbitals (especially the valence ones) and their interactions between atoms to form molecules. All of my college chemistry courses delved somewhat into quantum mechanics, with the biggest helping being in organic chemistry. And modern computational chemistry is basically modeling the QED as applied to atoms.
We use spectra to test QED calculations to something like 14 digits.
This is of course a brute-force approach. We currently lack, in all fields, theory for emergent properties. And the mass of the proton definitely is such.
Nevertheless, until now I have not seen anything that qualifies as "computing the masses".
Research papers like that do not contain any information that would allow someone to verify their claims. Moreover, such papers are much more accurately described as "fitting the parameters of the Standard Model, such as quark masses, to approximately match the measured masses", and not as actually computing the masses.
The published results of hadron masses are not much more accurate than you could compute mentally, without using any QCD, much less Lattice QCD, by estimating approximate quark masses from the composition in quarks of the hadrons and summing them. What complicates the mass computations is that while the heavy quarks have masses that do not vary much, the effective masses of the light quarks (especially u and d, which compose the protons and neutrons) vary a lot between different particles. Because of this, there is a very long way between a vague estimate of the mass and an accurate value.
For just about anything else, Newton has us covered.
Nothing major.
Part of the problem is that building bigger colliders, telescopes, and gravitational wave detectors requires huge resources and very powerful computers to store and crunch all the data.
We're cutting research instead of funding it right now and sending our brightest researchers to Europe and China...
I did physics at uni and kind of dropped out when it got too hard.
I've long guessed the incompatibility is because the maths is just too hard for human brains, though I'm probably biased there, and we'll get a breakthrough when AI can handle much more complex maths than us. Probably not so long till we find out on that one.
I once tried to write a simplified explanation for why a spin-2 quantum theory naturally results in something like general relativity and totally failed - man that stuff's hard.
I think that even if AI were to find a good unification of GR and QM, we wouldn't be able to test it. We might accept it without additional confirmation if it were sufficiently natural-feeling (the way we accepted Newtonian gravity long before we could measure G), but there's no guarantee that we'd ever be able to meaningfully test it.
We could get lucky -- such a theory might point at a solution to some of the few loose threads we get out of existing collider and cosmological measurements -- but we might not. We could be stuck wishing we had a galaxy-sized collider.
It's also kind of interesting how causality allegedly has a speed limit and it's rather slow all things considered.
Anyway, in 150 years we absolutely came a long way, we'll figure it that out eventually, but as always, figuring it out might lead even bigger questions and mysteries...
Why is quantization necessary for information storage? If you're speculating about a storage device external to our universe, it need not be constrained by any of our physical laws and their consequences, such as by being made up of finitely many atoms or whatever. It might have components like arbitrary precision real number registers.
And if you're speculating about a storage device that lives within our universe, you have a contradiction because it's maximum information capacity can't exceed the information content of its own description.
The charge of electrons is -1 and protons +1. It has been experimentally measured out to 12 digits or so to be the same magnitude, just opposite charge. However, there are no theories why this is -- they are simply measured and that is it.
It beggars belief that these just happen to be exactly (as far as we can measure) the same magnitude. There almost certainly is a lower level mechanism which explains why they are exactly the same but opposite.
When an electron-positron pair is formed from a vacuum, we get all sorts of interesting geometry which I struggle to grasp or picture clearly. I understand the fact that these are fermions with spin-1/2 can similarly be explained as localized defects in a field of particles with integer spin (possibly a feature of the exact same "defect" as the charge itself, in the photonic field, which is what defines an electron as an electron).
EDIT:
> However, there are no theories why this is -- they are simply measured and that is it.
My take is that there _are_ accepted hypotheses for this, but solving the equations (of e.g. the standard model, in full 3D space) to a precision suitable to compare to experimental data is currently entirely impractical (at least for some things like absolute masses - though I think there are predictions of ratios etc that work out between theory and measurement - sorry not a specialist in high-energy physics, had more exposure to low-energy quantum topological defects).
Or any of the more recent work that references it?
Quark's don't have integer charge
For some reason electrons have charge -3 then, that coincides with the proton charge for no good reason.
I mean, I guess you could say that charge comes from (or is) the coupling of the quark/lepton field to the electromagnetic field, and therefore if it's something that's quantized on the electromagnetic side of that, then quarks and leptons would have the same scale. I'm not sure that's the real answer, much less that it's proven. (But it might be - it's a long time since my physics degree...)
me too, just addressing that a fraction might as well be an integer with some redefinition of the fundamental charge.
eddies in the space-time continuum?
Consistent quantum field theories involving chiral fermions (such as the Standard Model) are relatively rare: the charges have to satisfy a set of polynomial relationships with the inspiring name "gauge anomaly cancellation conditions". If these conditions aren't satisfied, the mathematical model will fail pretty spectacularly. It won't be unitary, can't couple consistently to gravity, won't allow high and low energy behavior to decouple,..
For the Standard Model, the anomaly cancellation conditions imply that the sum of electric charges within a generation must vanish, which they do:
3 colors of quark * ( up charge 2/3 - down charge 1/3) + electron charge -1 + neutrino charge 0 = 0.
So, there's something quite special about the charge assignments in the Standard Model. They're nowhere near as arbitrary as they could be a priori.
Historically, this has been taken as a hint that the standard model should come from a simpler "grand unified" model. Particle accelerators and cosmology hace turned up at best circumstantial evidence for these so far. To me, it's one of the great mysteries.
> you have to accept there will eventually be (hopefully simple) coincidences between certain fundamental values, no?
When the probability of coincidence is epsilon, then, no. Right now they are the same to 12 digits, but that undersells it, because that is just the trailing digits. There is nothing which says the leading digits must be the same, eg, one could be 10^30 times bigger than the other. Are you still going to just shrug and say "coincidence?"
That there are 26 fundamental constants and this one is just exactly the same is untenable.
Imagine an object made of only red marbles as the 'base state'. Now you somehow manage to remove one red marble: you're at -1. You add a red marble and you're at +1. It doesn't require any other marbles. Then you go and measure the charge of a marble and you and up at some 12 digit number. The one state will show negative that 12 digit number the other will show positive that 12 digit number.
Assigning charge as being the property of a proton or an electron rather than one of their equivalent constituent components is probably a mistake.
Consider: in every known case where we have found a deeper layer of explanation for a "coincidence" in physics, the explanation involved some symmetry or conservation law that constrained the values to a small discrete set. The quark model took seemingly arbitrary coincidences and revealed them as consequences of a restrictive structure. auntienomen's point about anomaly cancellation is also exactly this kind of thing. The smallness of the set in question isn't forced, but it is plausible.
But I actually think we're agreeing more than you realize. You're saying "this can't be a coincidence, there must be a deeper reason." I'm saying the deeper reason might bottom out at "the consistent discrete structures are sparse and this is one of them," which is a real explanation, but it might not have the form of yet another dynamical layer underneath.
>I'm aware of the charge coming from quark
So it's not +huge_number because the number of quarks involved is small. Sure we still don't understand the exact reason, but it's hardly as surprising that, uh, charge is quantized...
Like we could accept coincidences if at the bottom is all turtles, but here we see a stack of turtles and a stack of crocodiles and we are asking why they have similar characteristics even if they are so different.
No. It’s almost certainly not a coïncidence that these charges are symmetric like that (in stable particles that like to hang out together).
Which makes every constant fair game. Currently, we don’t have a good process for explaining multiple universes beyond divine preference. Hence the notion that a random number settled on mirror whole sums.
Nïce
For example, pair production is:
photon + photon = electron + (-)electron
electron + photon = electron - photon
proton = neutron + electron + (-)neutrino
The precise why of this algebra is the big question! People are chipping away at it, and there's been slow but steady progress.
One of the "best" approaches I've seen is "The Harari-Shupe preon model and nonrelativistic quantum phase space"[1] by Piotr Zenczykowski which makes the claim that just like how Schrodinger "solved" the quantum wave equation in 3D space by using complex numbers, it's possible to solve a slightly extended version of the same equation in 6D phase space, yielding matrices that have properties that match the Harari-Shupe preon model. The preon model claims that fundamental particles are further subdivided into preons, the "charges" of which neatly add up to the observed zoo of particle charges, and a simple additive algebra over these charges match Feyman diagrams. The preon model has issues with particle masses and binding energies, but Piotr's work neatly sidesteps that issue by claiming that the preons aren't "particles" as such, but just mathematical properties of these matrices.
I put "best" in quotes above because there isn't anything remotely like a widely accepted theory for this yet, just a few clever people throwing ideas at the wall to see what sticks.
But again, this is just observation, and it is consistent with the charges we measure (again, just observation). It doesn't explain why these rules must behave as they do.
> This very, very strongly hints that the fundamental particles aren't actually fundamental in some sense.
This is exactly what I am suggesting in my original comment: this "coincidence" is not a coincidence but falls out from some deeper, shared mechanism.
Sure, but that's fundamental to observing the universe from the inside. We can't ever be sure of anything other than our observations because we can't step outside our universe to look at its source code.
> It doesn't explain why these rules must behave as they do.
Not yet! Once we have a a theory of everything (TOE), or just a better model of fundamental particles, we may have a satisfactory explanation.
For example, if the theory ends up being something vaguely like Wolfram's "Ruliad", then we may be able to point at some aspect of very trivial mathematical rules and say: that "the electron and proton charges pop out of that naturally, it's the only way it can be, nothing else makes sense".
We can of course never be totally certain, but that type of answer may be both good enough and the best we can do.
If the question is, why is quantum mechanics the correct theory? Well, I guess that's how our universe works...
And does it even apply here? If the charge on the electron differed from the charge on the proton at just the 12th decimal place, would that actually prevent complex life from forming. Citation needed for that one.
I agree with OP. The unexplained symmetry points to a deeper level.
i feel the same about many worlds
I was born to this world at a certain point in time. I look around, and I see environment compatible with me: air, water, food, gravity, time, space. How deep does this go? Why I am not an ant or bacteria?
Electrons are helically moving photons: https://www.researchgate.net/publication/281322004_The_elect...
That's some interesting/wacky stuff, but there has been more research to improve those calculations - like deriving the electron charge and magnetic moment.
Personally I like the idea that a proton is somehow literally an electron and 3 up quarks (a neutron gets 2 electrons and 3 up quarks). I am not a physicist though, so I'm sure there are reasons they "know" this is not the case.
I find it fascinating that some physicists say wave functions are somehow "real" and then we've got Jacob Barandes saying you don't even need wave functions to do the computations of QM: https://www.youtube.com/watch?v=7oWip00iXbo
IMHO there is a lot of exploration to be done without particle accelerators.
How do you explain that electrons have a rest mass, but photons don't (otherwise photons couldn't move with the speed of light according to special relativity)?
An electron gets it directle from the VEV.
If you tally up the forces, the difference is a residual attraction that can model gravity. It was rejected on various experimental and theoretical grounds, but it goes to show that if things don't cancel out exactly then the result can still leave a universe that would appear normal to us.
Some lean on the multiverse and the anthropic principle to explain it, but that is far less parsimonious.
Crackpots have found thousands of formula that try to explain the ratio of the proton to electron mass but there is no expectation that there is a simple relationship between those masses since the proton mass is the sum of all sorts of terms.
(I use quotes because those are emergent concepts)
Same as "hacker community" deciding that AI is worth FOMO'ing about
https://en.wikipedia.org/wiki/Super-Kamiokande
which targets many of those questions.
As for the "hacker community" I think AI is really controversial. I think other people find the endless spam of slop articles about AI more offensive than I do. It's obvious that these are struggling to make it off the "new/" page. The ones that offend me are the wanna-be celebrity software managers [1] who think we care what they think about delivering software that almost works.
[1] sorry, I liked DHH's industry-changing vision behind Ruby-on-Rails, but his pronunciations about software management were always trash. You might make the case that Graham worked with a lot of startups so his essays might have had some transferable experience but they didn't. Atwood and Spolsky, likewise. Carmack is the one exception, he's a genius
In other words: There can be multiple "layers" of linked states, but that doesn't necessarily mean the lower layers "create" the higher layers, or vice versa.
Now, the ratios between these charges appear to be fundamental. But the presence of fractions is arbitrary.
Actually, I doubt it. Because of their color charge, quarks can never be found in an unbound state but instead in various kinds of hadrons. The ways that quarks combine cause all hadrons to end up with an integer charge, with the ⅔ and -⅓ charges on various quarks merely being ways to make them come out to resulting integer charges.
Yes, that's part of the plan. I mean, not to all the physicists, just to those whose work doesn't bring in results anymore, and it hasn't for 30 to 40 years now. At some point they (said physicists) have to stop their work and ask themselves what it is that they're doing, because judging by their results it doesn't seem like they're doing much, while consuming a lot of resources (which could have been better spent elsewhere).
Thousands of people have worked on bringing LHC up during a few decades before, Higgs came to be, across all engineering branches.
This stuff is hard, and there is no roadmap on how to get there.
Did it? I thought the whole point was that the data that came from LHC showed that it was inconclusive and needed a bigger more powerful machine to prove it. Happy to be proved wrong.
Physics advances have been generally driven by observation, obtained through better and better instrumentation. We might be entering a long period of technology development, waiting for the moment our measurements can access (either through greater energy or precision) some new physics.
LLMs were a breakthrough I didn't expect and it's likely the last one we'll see in our lifetime.
Either way this is also opinion based.
There hasn't been a revolutionary change in technology in the last 20 years. I don't consider smart phones to be revolutionary. I consider going to the moon revolutionary and catching a rocket sort of revolutionary.
Actually I take that back I predict mars as a possible break through along with LLMs, but we got lucky with musk.
catching a rocket is very impressive, but its just a lower cost method for earth orbit. it does unlock megaconstellations tho
AI is the step function change. The irony is that it became so pervasive and intertwined with slop people like you forget that what it does now (write all code) was unheard of just a couple years ago. ai surpassed the hype, now it’s popular to talk shit about it.
However, from your later comments, it sounds as though you feel the only operating definition of a "breakthrough" is a change inducing a rapid rise in labor extraction / conventional productivity. I could not disagree more strongly with this opinion, as I find this definition utterly defies intuition. It rejects many, if not most, changes in scientific understanding that do not directly induce a discontinuty in labor extraction. But admittedly if one restricts the definition of a breakthrough in this way, then, well, you're probably about right. (Though I don't see what Mars has to do with labor extraction.)
To which AI is the only technology that has enough distance to be classified as a “breakthrough”.
A description that matches reality is realist, not pessimist.
This means that most people who you would term as "realists" are likely optimists and not realists at all.
If you mean nearest neighbours search like autocorrect then LLMs are extrapolative.
You can easily generate combinations not seen before. I mean you can prove this with parametric prompting.
Like "Generate a poem about {noun} in {place} in {language}" or whatever. This is a simplistic example but it doesn't take much to come up with a space that has quadrillion of possibilities. Then if you randomly sample 10 and they all seem to be "right" then you have proven it's not pure neighbour recall.
Same is true of the image generators. You can prove its not memorizing because you can generate random varients and show that the number of images realizable is more than the training data possibly contains.
If you mean on the underlying manifold of language and ideas. Its definitely interpolation, which is fundamentally a limitation of what can be done using data alone. But I know this can be expanded over iteration (I have done experiments related to this). The trick to expanding it actually running experiments/simulation on values at the boundry of the manifold. You have to run experiments on the unknown.
But I get it, the interpolation you’re talking about is limited. But I think you missed this insight: human interpolation is limited too. In the short term everything we do is simply recombination of ideas as you put it.
But that’s the short term. In the long term we do things that are much greater. But I think this is just an aggregation of small changes. Change the words in a poem 5000 times: have the LLM do the same task 5000 times. Let it pick a random word. The result is wholly original. And I think in the end this what human cognition is as well.
Even if an LLM came up with a theory of quantum gravity in some random chain of thought via chance, once the context is wiped everything is gone.
Expanding the frontier of knowledge (true extrapolation) requires iteration and layering of sinpler ideas. If you loose the layers and have to start from scratch every time then you fundamently will never move further out then what you already know (the interpolation).
You missed my point. I'm saying humans have finite context windows as well.
Look at how claude keeps passing it's context window down the chain. It creates a summary. It can spend thousands of tokens to coalesce on a conclusion, and only that conclusion needs to be passed on to the next context window. The research can be tossed. That's how human discovery works. We don't need the whole context window, we produce major discoveries because we pass the conclusion down the chain.
LLMs can do it too. We just never fully tried it.
It will give it to you.
The problem is that we've mostly explained everything we have easy access to. We simply don't have that many anomalies left. Theoretical physicists were both happy and disappointed that the LHC simply verified everything--theories were correct, but there weren't really any pointers to where to go next.
Quantum gravity seems to be the big one, but that is not something we can penetrate easily. LIGO just came online, and could only really detect enormous events (like black hole mergers).
And while we don't always understand what things do as we scale up or in the aggregate, that doesn't require new physics to explain.
And, I think, most people would place that kind of stuff under "solid state physics" anyway.
I will commit the first sin, by declaring without fear of contradiction the cat actually IS either alive or dead. it is not in a superposition of states. What is unknown is our knowledge of the state, and what collapses is that uncertainty.
If you shift this to the particle, not the cat, what changes? because if very much changes, my first comment about the unsuitability of the metaphor is upheld, and if very little changes, my comment has been disproven.
It would be clear I am neither a physicist nor a logician.
From the wikipedia page: “This thought experiment was devised by physicist Erwin Schrödinger in 1935 in a discussion with Albert Einstein to illustrate what Schrödinger saw as the problems of Niels Bohr and Werner Heisenberg's philosophical views on quantum mechanics.”
[0] Well, and the hidden variables are non-local, which is a whole 'nother can of highly non-intuitive worms.
However I still find it crazy that when you slow down the laser and one photon at a time goes through either slit you still get the bands. Which begs the question, what exactly is it constructively or destructively interfering with?
Still seems like there's much to be learned about the quantum world, gravity, and things like dark energy vs MOND.
(This is what I was told, exploring my belief it's always been fringes in streams of photons not emerging over repeated applications of single photons and I was wrong)
The difficult part is single photon _detectors_, they're the key technology to explore the single-photon version of Young's experiment (which originally showed that light has wave-like properties).
If I make the equivalent of a double slit experiment in a swimming pool, then generate a vortex that propagates towards my plywood slits or whatever, it's not really surprising that the extended volume of the vortex interacts with both slots even though it looks like a singular "particle."
why does nobody mention the fact the photon doesnt keep going through the same hole? like why is it randomly moving through the air in this brownian way? the laser gun doesnt move, the slit doesnt move, so why do different photons end up going through different holes?
Unless you believe in a hidden-variables theory, this is provably false, though, see Bertlmann's Socks etc.
"The analysis has been optimized using neural networks to achieve the smallest expected fractional uncertainty on the t¯t production cross section"
I remember I used a library (THE library) from a German university which was all the rage at that time.
What is more interesting currently is things like anomaly detection using ML/NN and foundational models..etc.
Nuclear physics (ie, low/medium energy physics) covers diverse topics, many with real world application - yet travels with a lot of the same particles (ie, quarks, gluons). Because it is so diverse, it is not dead/dying in the way HEP is today.
Scaling up particle colliders has arguably hit diminishing returns.
Fun fact: I got to read the thesis of one my uncles who was a young professor back in the 90's. Right when they were discovering bosons. They were already modelling them as tensors back then. And probably multilinear transformations.
Now that I am grown I can understand a little more, I was about 10 years old back then. I had no idea he was studying and teaching the state of the art. xD
You can find tensors even in some niche stuff in macroeconomics.
[1] https://home.cern/science/accelerators/future-circular-colli...
Heinz Wolff used to fill a similar role on British TV.
I wish those people focus on practical real world physics. So we all can enjoy new innovations.
Ever used GPS?
A CD player?
A laser?
Semiconductors?
>Cari Cesarotti, a postdoctoral fellow in the theory group at CERN, is skeptical about that future. She notices chatbots’ mistakes, and how they’ve become too much of a crutch for physics students. “AI is making people worse at physics,” she said.
The discovery of the Higgs boson in 2012 completed the Standard Model of particle physics, but the field has since faced a "crisis" due to the lack of new discoveries. The Large Hadron Collider (LHC) has not found any particles or forces beyond the Standard Model, defying theoretical expectations that additional particles would appear to solve the "hierarchy problem"—the unnatural gap between the Higgs mass and the Planck scale. This absence of new physics challenged the "naturalness" argument that had long guided the field.
In 2012, physicist Adam Falkowski predicted the field would undergo a slow decay without new discoveries. Reviewing the state of the field in 2026, he maintains that experimental particle physics is indeed dying, citing a "brain drain" where talented postdocs are leaving the field for jobs in AI and data science. However, the LHC remains operational and is expected to run for at least another decade.
Artificial intelligence is now being integrated into the field to improve data handling. AI pattern recognizers are classifying collision debris more accurately than human-written algorithms, allowing for more precise measurements of "scattering amplitude" or interaction probabilities. Some physicists, like Matt Strassler, argue that new physics might not lie at higher energies but could be hidden in "unexplored territory" at lower energies, such as unstable dark matter particles that decay into muon-antimuon pairs.
CERN physicists have proposed a Future Circular Collider (FCC), a 91-kilometer tunnel that would triple the circumference of the LHC. The plan involves first colliding electrons to measure scattering amplitudes precisely, followed by proton collisions at energies roughly seven times higher than the LHC later in the century. Formal approval and funding for this project are not expected before 2028.
Meanwhile, U.S. physicists are pursuing a muon collider. Muons are elementary particles like electrons but are 200 times heavier, allowing for high-energy, clean collisions. The challenge is that muons are highly unstable and decay in microseconds, requiring rapid acceleration. A June 2025 national report endorsed the program, which is estimated to take about 30 years to develop and cost between $10 and $20 billion.
China has reportedly moved away from plans to build a massive supercollider. Instead, they are favoring a cheaper experiment costing hundreds of millions of dollars—a "super-tau-charm facility"—designed to produce tau particles and charm quarks at lower energies.
On the theoretical side, some researchers have shifted to "amplitudeology," the abstract mathematical study of scattering amplitudes, in hopes of reformulating particle physics equations to connect with quantum gravity. Additionally, Jared Kaplan, a former physicist and co-founder of the AI company Anthropic, suggests that AI progress is outpacing scientific experimentation, positing that future colliders or theoretical breakthroughs might eventually be designed or discovered by AI rather than humans.
The best known example is the pre- and post-Copernican conceptions of our relationship to the sun. But long before and ever since: if you show me physics with its wheels slipping in mud I'll show you a culture not yet ready for a new frame.
We are so very attached to the notions of a unique and continuous identity observed by a physically real consciousness observing an unambiguous arrow of time.
Causality. That's what you give up next.
Copernicus was proposing circular orbits with the sun at the center instead of the earth. The Copernican model required more epicycles for accurate predictions than the considerably well-proven Ptolemaic model did, with the earth at the centre.
It wasn't until Kepler came along and proposed elliptical orbits that a heliocentric solar system was obviously a genuine advance on the model, both simpler and more accurate.
There was no taboo being preserved by rejecting Copernicus's model. The thinkers of the day rightfully saw a conceptual shift with no apparent advantage and several additional costs.
I'm holding a big fat Citation Needed banner. Seemingly none of these "thinkers of the day" took it far enough to write down the thoughts.
While at it, were the "thinkers of the day" fond of the idea of Ptolemy's equant?
Let me put it this way. Once upon a time people didn't know about solar eclipse. But then a day came when a certain somebody was instantly promoted to a Lead Staff Senior Astronomer, just because they predicted to the hour that the sun is going to disappear.
Well, but think about the field just one day before that:
- maybe 10 theories that said "it's just a reformulation/refactoring, nothing to see here, all business as usual, no new predictions, very safe for the author",
- maybe 100 crackpot theories. Undoubtedly, unashamedly crackpot, with wild predictions all over. Of which 99% were in fact pure trash, so, retrospectively, people were rightfully considering them trash. Yet 1 was the key to progress.
Depends on how big a scale you pick:
https://en.wikipedia.org/wiki/Conservation_of_energy#General...
https://en.wikipedia.org/wiki/Cauchy_horizon
:)
- the universe as a Neural Network (yes yes moving the universe model paradigm from the old Clockwork to machine to computer to neural network)
I found it interesting and speculative but also fascinating
See video here:
https://youtu.be/73IdQGgfxas?si=PKyTP8ElWNr87prG
AI summary of the video:
This video discusses Professor Vitaly Vanchurin's theory that the universe is literally a neural network, where learning dynamics are the fundamental physics (0:24). This concept goes beyond simply using neural networks to model physical phenomena; instead, it posits that the universe's own learning process gives rise to physical laws (0:46).
Key takeaways from the discussion include: • The Universe as a Neural Network (0:00-0:57): Vanchurin emphasizes that he is proposing this as a promising model for describing the universe, rather than a definitive statement of its ontological nature (2:48). The core idea is that the learning dynamics, which are typically used to optimize functions in machine learning, are the fundamental physics of the cosmos (6:20). • Deriving Fundamental Field Equations (21:17-22:01): The theory suggests that well-known physics equations, such as Einstein's field equations, Dirac, and Klein-Gordon equations, emerge from the learning process of this neural network universe. • Fermions and Particle Emergence (28:47-32:15): The conversation delves into how particles like fermions could emerge within this framework, with the idea that useful network configurations for learning survive, similar to natural selection. • Emergent Quantum Mechanics (44:53-49:31): The video explores how quantum behaviors, including the Schrödinger equation, could emerge from the two distinct dynamics within the system: activation and learning. This requires the system to have access to a "bath" or "reservoir" of neurons. • Natural Selection at the Subatomic Scale (1:05:10-1:07:34): Vanchurin suggests that natural selection operates on subatomic particles, where configurations that are more useful for minimizing the loss function (i.e., for efficient learning) survive and those that are not are removed. • Consciousness and Observers (1:15:40-1:24:09): The theory integrates the concept of observers into physics, proposing a three-way unification of quantum mechanics, general relativity, and observers. Consciousness is viewed as a measure of learning efficiency within a subsystem (1:30:38).
Maybe you aren’t going to be satisfied with the sort of complicated mathematics which appears to be correct (or, on the right track).
If you have complaints about the aesthetics of how the universe works, take it up with God.
Personally, I think there is a lot of beauty to be found in it.
I’ll admit that there are a few parts that go against my tastes (I don’t like needing to resort to distributions instead of proper functions), but that’s probably just intellectual laziness on my part.
This is truly a copout. When science faulters in explaining the world we get answers like this. His argument isnt with the universe, but with out own scientific theories. If you dont want your theories about the physical world to explain physical world, then be an engineer. Science explains the world, engineers use those theories. QM has large gaps and doesnt actually explain much, but I guess the universe doesnt care whether our theories are wildly off the mark or not.
The excellent Arvin Ash has a very accessible video about it: https://www.youtube.com/watch?v=paQLJKtiAEE
The “What path did the photon take?” question is one of those times. The answer to the question is Mu.
Similar to the questions “How much phlogiston is there in iron?” or “Does sulphur have more earth than air, or more air than earth?”.