The fundamental theories we have is Quantum Electrodynamics and Quantum Chromodynamics.
This new experiment tells you that "modern nuclear forces, including those derived within chiral effective field theory" break down and cannot be used to describe what they observed. Here is the arxiv: https://arxiv.org/abs/2112.10582
It just tells you that their effective theory is no longer effective in these circumstances. Unless you actually observe something contradicts QED+QCD calculations, nothing fundamental is wrong.
I can't believe they pick such a clickbaity title for a serious publication and let quanta magazine publish an even more clickbaity article about it. Well, I guess they need more funding.
[EDIT] PS. The science is sound and suggests that nuclear physicists must refine their theories to match observations. This also encourages those working on QED+QCD, as increased computational power may enable precise form factor calculations for comparison with experiments.
The title says that the experiments diagree with "the leading theory of the nucleus", which is chiral effective field theory. I don't see anything wrong or "clickbaity" about this.
I would characterize it as the article doesn't have anything overtly wrong with it, but it did make it easy to come away thinking this is revealing some sort of massive fundamental issue with everything, rather than what it is, which is the continuing process of tuning a highly successful theory down in the decimal points.
Whether or not you consider that to be part of their job is in the eyes of the reader.
That's not at all what's going on here. EFT is a limit of a more fundamental theory which is already known. Orbital mechanics were a limit of a more fundamental theory that was NOT known at the time.
Sorry, but unless you're a physicist, why would you expect to be able to know the significance of the paper? If you walked away misunderstanding the implications, then I gotta ask - assuming you're in software - are you careful to proofread your papers to ensure a geologist doesn't misunderstand them?
"Sorry, but unless you're a physicist, why would you expect to be able to know the significance of the paper?"
Because I expect a news article on the topic to clearly contextualize that answer. That is a core component of their job.
Quanta magazine is pretty good in most things I read, but I feel like they drop this particular ball pretty often. I suppose that concession to clickbaitery is the bare minimum anyone can survive with nowadays. But they are still several cuts above most things I read.
"Theory of the nucleus" does not necessarily imply just QED+QCD in this context. It can mean something derived from QED+QCD - the theory of which elements of the calculation can be thrown out from the QED+QCD calculations. That would be hardly the first theory which is a derived theory from a more fundamental theory. So the headline is fine? For once Quanta was less clickbaity than the preprint.
I think you're reacting to things the paper doesn't say - they never claim any new physics. EFT is a simpler model than what you'd derive from QCD and it makes sense it'll be wrong in some limits. The paper finds such a limit. That's all? The paper title and abstract seem to be pretty accurate? Or are you objecting to the characterization of EFT as "theory"?
If so, then how about planet formation theory, or solid state physics? Are those also not theories, because they're ultimately just limits of the standard model?
> I can't believe they pick such a clickbaity title for a serious publication and let quanta magazine publish an even more clickbaity article about it. Well, I guess they need more funding.
My take from reading the article (not a physicist) is the physics of the nucleus (i.e. the protons and neutrons and strong nuclear force) are treated as emergent phenomena from the quantum theories about fundamental particles (e.g. quarks, leptons & gluons).
Per the article, such leading theory of the nucleus is "chiral effective theory," which seems to be quite inaccurate at making predictions for the experiment in question.
I'm not sure how much more accurate the headline could be, unless chiral effective theory is not in fact the ex ante leading theory of the nucleus.
why do we clutch pearls whenever a publication uses a "click-baity" title? at least it manages to a: get people to actually read the publication, and b. publisher/site makes money. nobody's running a charity of information in a capitalist society.
Having an standard of truth is important as a reputation for an organization(whether for commercial or non-commercial reasons). Besides, click-baitiness is not sustainable as in the equilibrium, readers will change expectations to assume artices are click-baity and information on the real breakthroughs will have fight all the fake breakthroughs.
BTW, This is not about Quanta which I find is a really good resource. Although, there might indeed be some click-baitiness not with the motive of profit(you could describe it as a charity run by Jim Simons), but in the sense of someone trying to get students interested with a provocative title for a science talk.
agreed. It's a fine line that publishers have to walk between capturing attention and maintaining credibility. As you've said, the long-term sustainability of clickbait is questionable. It's a short-term strategy that may inflate traffic numbers, but can lead to a loss of trust over time.
The challenge is to strike the right balance between making content appealing and keeping it accurate and valuable, especially crucial with scientific publications, where the accuracy and trustworthiness of information is paramount.
> Instead, at these scales, a new effective force emerges — the strong nuclear force, transmitted between nucleons by the exchange of pions.
I'm admittedly ignorant, but I'm not convinced that a lot of theoretical physics is basically curve fitting where you've got a model with enough flexibility that you can make it fit the data. String theory always seemed like an egregious version of this, I think it's less popular now.
I think that's why elegance goes a long way in theories: a simple and concise description is harder to overfit.
The standard model has a number of free parameters [1] but the results of calculations are pretty sensitive to them, and this is what predicted (not just explained post-hoc) the Higgs. It's not incorrect to say there's curve fitting involved, but it severely understates the magnitude of the achievement that is the standard model, and its success in explaining everything that underpins everyday life[2], as well as most things beyond that regime[3]
There's also the problem of fine tuning -- why is the fine structure constant roughly 1/137? If it were different from its current value by a tiny amount, the universe as we know it wouldn't exist. Is the anthropocentric principal the only explanation we have -- it has the value it has because it produces a universe in which we're able to observe it?
And I guess less formally there's also the problem of complexity: condensed matter physics exists because trying to solve the standard model for a solid directly is both incredibly infeasible (think "cost of flipping bits in the calculation far extends that of all matter in the observable universe") and fails to capture the emergent phenomena in a natural way.
The other theory is there are infinite universes somehow being created all the time by every choice. Which to my mind isn't very Occam's Razor-ish. But it does exist as a theory.
You mean the Many-Worlds interpretation? That's not every choice, but every quantum measurement. And it's not necessarily an infinite number. And it's not a theory, but an interpretation. And it's actually very Occam's Razor-ish (at least that's what proponents claim), because it needs less postulates than the standard Copenhagen interpretation. The many worlds are a consequence, not a postulate.
IMHO, "Inflation" is false theory, because it doesn't obey law of conservation of energy.
If no inflation, then no Big Bang, so our Visible Universe is much older.
If our Universe is much older, then life evolved multiple times already. Red stars are shallow gravity wells, so they are primary target of an expansive civilization, because it easy to enter/exit them, so they are colonized first and their light is captured fully.
Conservation of energy is not the fundamental law it is often presented as. It is derived from Noether's theorem as applied to descriptions of the universe. Locally, it is true that energy is conserved, however, IIRC, General Relativity already can break it at large scales, even before we consider the fact that GR is incomplete and the real theory may break it even harder.
It is possible and I would judge even likely that some other value is conserved; that conservation of energy can be broken doesn't mean all chaos is unleashed and the Patent Office should revoke their ban on perpetual motion machines. When it is finally worked out, we may even pick up our "energy" label and move it to this new quantity. Depends on a lot of details we don't currently know. But what we today call energy is not necessarily conserved at large scales.
Saying that the universe can't do X because it violates conservation of energy is a circular argument; the precise definition of "conservation of energy" used by physics today is derived from our belief that the universe can't do X, but we also know our beliefs are incomplete. Very good approximations. Don't quit your day job to build a perpetual motion machine. But we are not in a position yet to even claim that our description of the universe is complete and we know the exact thing being conserved.
Cool story. Now explain why almost everything we see is moving away from us, where fresh hydrogen for stars comes from in an ancient universe, where the cosmic background radiation comes from, why the distant universe appears 'younger'...
Note that the 'laws' of physics are no better than normal scientific theories, scientists just had more hubris back then.
> Now explain why almost everything we see is moving away from us
(Not a native speaker).
Most galaxies in our galaxy cluster are moving away from us because of coincidence: Shappley attractor makes accretion disk by attracting mater from Dipole Repeller void[0], so our local group of galaxies is stretched along the way. At scale of our local galaxy cluster, Doppler Shift is responsible for majority of Red Shift.
At cosmic scale, Red Shift cannot be explained by Doppler Shift alone. If we take into account gravitational waves, then at least part of Red Shift can be explained by gravitational noise: gravitational waves are slowing down light a bit, so photon loses tiny bit of energy with every such interaction, which causes major part of Red Shift at cosmic scale.
> where fresh hydrogen for stars comes from in an ancient universe,
This is though question which is hard to answer. If elementary particles are bubbles, then they are popping up because something is stretching our Universe, i.e. our Universe is inflating ... oh, fck.
> where the cosmic background radiation comes from
[If inflation theory is false, no Big Bang, and visible Universe is much older, then]
Cosmic microwave background is just light from distant galaxies with large Red Shift z=1000 (light was stretched about 1000 times from galaxies in range of about 4 trillion light years).
> why the distant universe appears 'younger'...
James Webb infra-red telescope is proving that this assumption is false right now. Read the news.
We have a good idea where it comes from: It was created in the big bang, and as stars form (and explode, or form neutron stars and collide) they turn it into heavier elements. Over time there is less hydrogen, which is why the universe can’t be infinitely old. Since it’s only ~13.7B years old, the amount of hydrogen we see makes sense with our models.
It’s a much much bigger problem if the universe significantly older than we think it is… if we were to believe the Wikipedia article on this[0], we’d only expect stars to exist at all for about 100 trillion years, but given that the distribution of hydrogen availability is likely to follow an inverse exponential decay curve of some sort, we’d probably see much lower amounts of hydrogen much earlier than that.
> because it doesn't obey law of conservation of energy.
Energy is in general only conserved locally. More precisely, the covariant derivative of the stress-energy tensor `\nabla_{\mu}T^{\mu \nu}` is zero, but this can only be put into integral form in a few special cases.
General Relativity doesn’t end just above the atmosphere and quantum mechanics ought to apply to everything, not just experiments.
The current microscopic models don’t even attempt to explain how a molecule of water is lighter than the oxygen and two hydrogen atoms that went into making it.
Oh sure, we can wave our hands at it and invoke the mass-energy relation from GR, but this doesn’t “pop out” of the Standard Model in any sense.
This isn’t some exotic phenomena only found in deep space!
We have a long way to go before we can par ourselves on the back and claim to truly understand what’s going on.
> General Relativity doesn’t end just above the atmosphere and quantum mechanics ought to apply to everything, not just experiments.
No one disagrees, but if it were that easy to just jump straight to the final theory we would have done it long ago. For now, effective theories are all we've got.
> Oh sure, we can wave our hands at it and invoke the mass-energy relation from GR, but this doesn’t “pop out” of the Standard Model in any sense.
Yes, it does. You don't need GR for mass-energy equivalence, just special relativity. And the Standard Model is fully special-relativistic.
> We have a long way to go before we can par ourselves on the back and claim to truly understand what’s going on.
This is a misconception of scientific endeavour in general and of physics in particular. All models are approximations of reality. We have a theory that is consistent with experimental observations, then we make observations with which the theory is not consistent anymore and we develop a new theory that explains those new observations as well, and so on. We will never have an "exact" model, whatever that even means. But we have models that have limitations that are far beyond what's relevant for most people's life.
At many points in time, we could pat ourselves on the back. The heliocentric model. Newtons model. General Relativity. The Standard Model. All these models were important steps forward and led us to where we are today, which is absolutely astonishing. No, we don't have a full theory explaining everything, but we never will.
> Oh sure, we can wave our hands at it and invoke the mass-energy relation from GR, but this doesn’t “pop out” of the Standard Model in any sense.
Mass-energy equivalence, a.k.a. E=mc^2, is special relativity. It's fundamentally linked with our understanding of electromagnetism. Physics students generally learn about special relativity before they get to quantum mechanics.
You appear to be confusing special relativity and general relativity. Mass-energy equivalence pops out of special relativity, and is part of general relativity because GR extends SR. Another class of theories which extend special relativity are (relativistic) quantum field theories. These also have mass-energy equivalence baked into them because they contain special relativity.
Your are correct that there is a (strong) conflict between general relativity and quantum field theory, and this is a major problem for theorists, but it does not pose problems for using mass-energy equivalence in quantum field theories (since it comes from SR not GR).
There are real, physical, examples where the GR/QFT conflict is more problematic. For example in quantum physics labs around the world it is possible to put things which have mass in superpositions of being in two different places. This is usually done with very small objects, but it happens. We have absolutely no idea what is happening to space-time when we do this.
Nothing says mass-energy equivalence cannot be applied to small particles. We have a good explanation of a very large set of physical phenomena. Yes, there are always things that are unknown and more you know, the more there is to know at the edges.
No one is claiming to "truly" understand anything and your cynicism is misplaced.
You mean experimental evidence? I don't think our mass measurements are that precise.
Just to be clear, that statement is very well accepted physics, and we have plenty of evidence of bounding energy changing the mass of things on the more energetic reactions (the nuclear ones). It would be incredibly surprising (in "redo all of physics" surprising) if it didn't hold for chemical reactions too, but I don't think anybody has evidence.
You mean experimental evidence? I don't think our mass measurements are that precise.
You don't need to weigh individual atoms or molecules to take measurement!
Just to be clear, that statement is very well accepted physics, and we have plenty of evidence of bounding energy changing the mass of things on the more energetic reactions (the nuclear ones). It would be incredibly surprising (in "redo all of physics" surprising) if it didn't hold for chemical reactions too, but I don't think anybody has evidence.
Not sure I follow your direction here. Seems to be a conflation of three separate things, not necessarily compatible with each other. In classical physics mass and charge (of a particle) are different properties. One defines how particle behaves in response to forces, the other how it interacts with em fields. That's one. The other, if we go into relativistic physics, there's mass-energy equivalence (as stated by einstein)... however, charge itself isn't a form of energy, BUT charged particles can have energy associated with their electric fields that would contribute, in a sense, to the overall mass-energy of a system (which is usually ignored unless we're talking sub-atomic particles or high-energy physics). That's two. And then there's binding (not bounding) energy which represents the amount of energy required to split a system of particles into its non-interacting components (such as, in context of nuclear physics, splitting a nucleus into protons and neutrons).. or you've meant electron binding energy which represents amount of energy needed to remove an electron from an atom.. that'd be a third.
The mass ratios of charged particles, such as atomic and molecular ions, can be measured incredibly accurately in Penning traps. Some of the most accurate comparisons are between the mass-3 ions ³He⁺, HD⁺, T⁺, and H₃⁺. Of these, only H₃⁺ has long-lived excited states, and the different excitation energies are clearly resolved in the mass comparisons [1]. The binding energies are much larger and have to be taken into account in the comparisons.
> Can you point to some evidence for the claim that "a molecule of water is lighter than the oxygen and two hydrogen atoms that went into making it?
Not OP, but burning hydrogen in oxygen is exothermic. It makes intuitive sense that the energy from that reaction no longer contributes to the mass of its products.
"
The weight of a molecule of water (H2O) is the sum of the weights of the two hydrogen atoms and one oxygen atom that compose it. Here are the atomic weights of these elements:
Hydrogen (H): Approximately 1 atomic mass unit (amu)
Oxygen (O): Approximately 16 amu
So for a molecule of water:
2 Hydrogen atoms: 2 * 1 amu = 2 amu
1 Oxygen atom: 16 amu
Adding these together gives a total of 18 amu for a molecule of water.
This means that a molecule of water has the same weight as the sum of the weights of the two hydrogen atoms and one oxygen atom that compose it, because the molecule is simply a combination of these atoms. There's no loss or gain in weight when the atoms combine to form the molecule.
However, this does not take into account the minor decrease in mass that occurs during the formation of a water molecule due to the conversion of some mass into binding energy according to Einstein's equation E=mc^2. This decrease is incredibly small and generally not considered in standard atomic weight calculations, but it does technically make the water molecule ever so slightly lighter than the sum of its constituent atoms."
> the minor decrease in mass that occurs during the formation of a water molecule due to the conversion of some mass into binding energy according to Einstein's equation E=mc^2
Is highly imprecise at best, and misleading at worst.
It is true that the mass of the water molecule is slightly less than that of the oxygen and hydrogen atoms combined. It is not true that this excess mass is converted into "binding energy", binding energy is negative in stable molecules. That is the binding energy measures how much energy you would have to add to break up the molecule, or conversely, how much energy is lost (as heat/light/whatever) to the environment when the molecule is formed.
The mass is lower because it has been converted into heat in the environment, not because it has been converted into binding energy.
---------------
I would call this an instance of the language model producing convincing sounding nonsense (something that they do quite often when asked about technical stuff).
Okay, somebody explain these downvotes, because afaik none of these statements in this comment or the other downvoted comments about the mass of water are incorrect. Somebody make it make sense.
I believe this one is downvoted for quoting Chat GPT. The other one is downvoted not so much for the claim about water molecule mass, but because of the combative tone and feeling that it is challenging established physics in a somewhat shallow way, most likely.
It cracks me up that my comment is seen as "challenging established physics" (and being downvoted into oblivion) when literally everything I stated is established physics.
I really don't see what's controversial about what I've said that's riled up people so much...
It is factually incorrect in the assertion that the standard model can't explain the reduction in mass (special relativity and quantum mechanics work fine together. It's general relativity that is the problem). In fact mass-energy equivalence is a pretty core part of quantum mechanics.
> In fact mass-energy equivalence is a pretty core part of quantum mechanics.
It may be stated as such, and added in to equations as an external piece of knowledge from relativity, but this is cheating a bit.
Essentially, when we state that H2O has less mass than H+H+O, what we actually mean is that H2O bends spacetime a little bit less than the three atoms individually that made it up. There's no accepted variant of QM or the Standard Model that explains this. The dynamics of spacetime curvature rearranging as the photon is emitted as the hydrogen atoms burn is not explained by modern science. This is fundamentally the "QM is incompatible with GR" issue.
My point was that it isn't just near black holes that a GR-compatible microscopic theory is relevant.
It's relevant even in the flame of a candle. It's a small effect, but it's there. The inconsistency in the theories occurs at all scales.
While you're right about the inconsistency between GR and QM applying at any level, you're wrong about needing GR to talk about the mass of the water molecule.
Even in pure QM, the water molecule will have less inertia than unbonded hydrogen and oxygen atoms. This should in principle be measurable by applying a known force to the water molecule and to the three atoms, and measuring their acceleration. The difference should perfectly match the inertial difference predicted by SR and GR.
GR adds the observation that, if the water molecule has less inertia, it should also bend space-time less, and it is this bending of space time that can't be explained by QM.
Though I should add that I've had a reply to a different comment once that explained that QM is actually compatible with the flat-ish but not perfectly flat space times that GR predicts anywhere not very close to a black hole. They were claiming that in fact modern QFTs can even predict things like the gravitational lensing produced by our sun, and that they only break down when near the event horizon of a black hole.
> Essentially, when we state that H2O has less mass than H+H+O, what we actually mean is that H2O bends spacetime a little bit less than the three atoms individually that made it up. There's no accepted variant of QM or the Standard Model that explains this.
I'm not sure this is correct. It bends spacetime less simply because it's in a lower energy state. It's correct to say that the Standard Model doesn't explain spacetime curvature, but the curvature in GR is implied by the energy which is explained.
To oversimplify: the Standard Model is pretty great when you've got two particles. As soon as there's three, it's too hard to calculate most things people are interested in. Oh, or gravity. Gravity's a problem too.
"everything that underpins everyday life" is not everything. A more precise way to put it would be that we understand physics at the energy scales we've been able to probe.
The operation of a D-type flip-flop and NAND gates explains everything in computers upwards of digital logic. What else is there to explain or explore in software?
Mmm, I don't agree with your analogy. Yes, you can model things at a higher level, but surely that is for efficiency, not because the model breaks down, in terms of accuracy.
In contrast, there are phenomenon which we know standard particle physics and quantum mechanics gives the wrong answere (despite getting so much else right).
higher-level models are not just for efficiency (though they are mandatory for that: quantum mechanics is intractable to solve directly for even a carbon atom). They also are important for understanding. These two problems are much bigger in terms of applying the standard model for the purposes of 'explaining everything' than the problem of the edge cases it does not explain accurately even in principle.
'everything that underpins daily life' does not include everything in the universe, for example it excludes dark matter and dark energy, neither of which matter at planetary scales like here on earth.
There's nothing preventing the formation of galaxies, stars and planets if you take away dark energy. Dark matter is not as clear cut but it's still likely to be unimportant.
Experimental physics works a bit differently than most people think. While string theory was/is popular, very few hold it as certainty. From the very beginning the discussions around it were that it was a non-testable theory. While out-group conversations around physics are "physicists believe" in-group conversations are more "the leading theory is". Uncertainty is deeply ingrained in the study and the focus is more around making our knowledge less wrong rather than proving something correct/making our knowledge correct. Subtle, but notably different. It is the reason you always see quotes with qualifiers like "should" or "we think" and rarely certainty (easy to miss if you aren't looking).
These distinctions matter when you create experiments and interpret results. They generally don't matter to the layman, since an authoritative answer is good enough. But they do matter if you need to do any form of evaluation, as essentially what I'm talking about is the importance of including error and uncertainty. Which btw, particle physics often has a uniquely tight bound: 5 sigma. You'll even notice CERN's blog post about 5 sigma has lots of qualifiers, does not suggest it claims certainty, how it isn't alone enough, and even references that there are good arguments for even higher bars. It's a different language than people are used to.
I don't get why the arguments are confined to string theory. The standard model plus general relativity are so good that any theory that resolves the conflict is necessarily only testable when you've got a stellar mass black hole in your lab.
That could be a call to stop bothering with exploring the domain entirely as infeasible. But I don't understand why string theory gets singled out for finger waggling when any other theory must run into the same problem.
No serious physicist only considers String Theory. That's part of the point I was making. Really String Theory is only a guide used while we wait for something better and more testable to come along. Nothing is set in stone, they are just guides to being less wrong.
What passes the bar for "elegant enough"? Why would laws of nature care about such human principles? And, most of all, why treat elegance as a guiding principle when all it has done is produce models incapable of being accurate outside a narrow range?
No.. In fact by the standards of the day, an circular orbit is more elegant. Think about circles within circles and the entire universe revolving around you.
To some extent, models that made less assumptions tend to be more correct.. but I think those are few and far between. We are now trying to explain very small discrepancies (by human scale) and the models are necessarily more complex.
Correct in a narrow range. Newton's elegance failed to accurately predict orbits of even our rather typical stellar system. Good for a start, but hardly something to strive for once we know better. So where do we go next? There is a real chance of artificially keeping ourselves in a local minimum if we don't seriously consider inelegant theories. It'd be neat if someone came up with an elegant theory that accurately described nature from quantum fields to stars. It'd also be neat if someone did that with an inelegant theory.
But that could just be a consequence of biases in the scientific process, right? After all phenomena that can be explained by simple/elegant theories are found, the remaining unexplained phenomena can only be explained by complicated/inelegant theories.
The theory they’re talking about is not just curve fitting. Instead only pieces which match the physics of QCD / the Standard Model Are included. It is simple to write down terms that you might include in a “just make up enough terms until it fits” methods that are excluded based on the requirements of symmetry matching that the whole program of EFT is organized around.
I think the "butterfly collecting phase" in particle physics was really the 40s and 50s, when a whole bunch of surprising new particles were discovered.
We are not now discovering any new unexpected particles (or any theoretically expected ones, since the Higgs), which is a bit unfortunate in terms of giving theorists something to work with.
String theory looks like a good math framework to describe possible universes. Physics today is hindered by the obsessive idea that what we see around - the observable universe - is all there is, rather than just one of many possible worlds. This is the good old geocentric model on steroids. And this is why physicists are puzzled by the lucky combination of constants that define our world.
This is great news, if it holds up. There hasn't been a lot of remarkable advancement in physics since the Standard Model.
"Another topic that comes up is simplicity. According to Feynman, nature is usually much simpler than our thoughts. Therefore, when trying to explain phenomena, we tend to overcomplicate things. Often, in the end, reality can be explained by much simpler terms. We just need to look at it from another point of view."
The problem with the nucleus is that the internal dynamics there are impossible to describe with any reasonable precision.
If for the electron shell we can calculate pretty much anything we want from the first principles (energy spectra, the half-lives of unstable and metastable states, etc.), we can't do anything similar for the nucleus.
For example, we can't compute half-lives of unstable nuclear isotopes. The best models are on the level of "imagine that a nucleus is a drop of water" or "assume that a nucleus is a potential well that contains an alpha particle".
And no, this is not a fundamental theory issue. We can describe the behavior of individual nuclear particles just fine at the energies that exist within the nucleus. It's their interaction that is completely baffling.
> If for the electron shell we can calculate pretty much anything we want from the first principles (energy spectra, the half-lives of unstable and metastable states, etc.), we can't do anything similar for the nucleus.
As I understand it, we can only really do that for a single-electron atoms. Multi-electron interactions get the same problem as inside the nucleus.
No, the problems are very different. The properties of multi-electron atoms can actually be calculated reasonably accurately with numerical methods, but including relativistic and quantum electrodynamic corrections is much harder than in single-electron systems. On the other hand, the coupling constant of the strong interaction is too large to permit perturbative calculations of bound systems. This makes calculations of nuclear properties fundamentally much more difficult, regardless of the particle number.
It doesn’t sound like this is necessarily a challenge to the Standard Model, only to one of the ways of approximately deriving predictions about the strong force.
For real, I wonder if Physicists are not putting themselves in a corner by using equations that are in principle "easy to work with" (because they're pulled from similar phenomenon) but a pain to actually use
Feynman diagrams are a visual way of representing a boatload of very complex equations and the worse part is that they work! But maybe it's a failure of math more than physics
"It’s possible that simply including more terms in the approximation of the nuclear force might be the answer. On the other hand, it’s also possible that these ballooning helium nuclei have exposed a fatal flaw in our understanding of the nuclear force."
I am far from an expert. But from the article, it seems to me to be more likely that it casts doubt on the approximations they're using to do the calculations.
That's my understanding: the math required to get a concrete prediction of a model is complicated enough that “either the theory, or the experiment, is wrong” excludes the most likely possibility: that too much error is being introduced by the approximations that they're (necessarily) using to get a tractable computation out of the model.
if we have to come up with a completely new model, we should at the same time reduce confusion going forward by renaming the new model to "the nucular model of the nuculus".
I am not a physicist but if I were to take a stab at simplifying things I’d assume that a neutron is probably just a proton and an electron… isn’t that what a neutron decays to once it has been ejected from a nucleus anyways?
I mean, it's not a bad theory. The wikipedia article on neutrons discusses how this was an assumption somewhat like this about 100 years ago ("nuclear electrons") and the lines of reasoning that led to abandonment of the idea: https://en.wikipedia.org/wiki/Neutron#Discovery -- it has to do with the observable quantity called "spin"; the spin of a neutron is not the sum of the spin of an electron and a proton, so it must be something else.
“The complexity of the proton and of the neutron seems to be real, and not due to a lack of knowledge on the part of physicists. We have equations that we use for describing quarks, anti-quarks and gluons, and the strong nuclear forces that they exert on one another. [These equations are called “QCD”, short for “quantum chromodynamics”.] We can check the accuracy of those equations through many different measurements, including the rates for producing various types of particles at the LHC. And when we put the QCD equations into a big computer, and make the computer calculate the properties of protons and neutrons, and other similar particles (collectively called “hadrons”), the computer’s predictions for the properties of these particles closely resemble what we see in the real world. So we do have good reason to believe that the QCD equations are right, and that our knowledge of the proton and neutron is based on the right equations. Yet having the right equations isn’t enough by itself, because
• simple equations can have very complicated solutions, and
• sometimes it is impossible to describe complicated solutions in a simple way.
As far as we can tell, that is the situation with nucleons: they are complicated solutions to the relatively simple equations of QCD, and there seems to be no way to describe them in a few words or pictures.”
Probably the most straightforward and stark demonstration of why a neutron can't be just a proton, electron and neutrino all stuck together is that it entirely fails to explain where all the rest of the particles come from when you have a jet: https://profmattstrassler.com/articles-and-posts/particle-ph...
This new experiment tells you that "modern nuclear forces, including those derived within chiral effective field theory" break down and cannot be used to describe what they observed. Here is the arxiv: https://arxiv.org/abs/2112.10582
It just tells you that their effective theory is no longer effective in these circumstances. Unless you actually observe something contradicts QED+QCD calculations, nothing fundamental is wrong.
I can't believe they pick such a clickbaity title for a serious publication and let quanta magazine publish an even more clickbaity article about it. Well, I guess they need more funding.
[EDIT] PS. The science is sound and suggests that nuclear physicists must refine their theories to match observations. This also encourages those working on QED+QCD, as increased computational power may enable precise form factor calculations for comparison with experiments.