Virtual particles do not necessarily have an invariant mass. That's why you can find examples of typically huge particles inside protons. That's why a beta decay of a neutron can involve the production of a virtual W- boson that has an invariant mass that's 86 times more massive than the neutron.
Also virtual particles don't make sense in a non-perturbative regime like room-temp protons, since they are an aid to understanding terms in the perturbation series expansion.
Not sure how they even apply in the case where Feynman diagrams aren't applicable. Hell, the calculations likely use lattice QCD which eschews them entirely!
Protons are non-perturbative, indeed, but this does not mean that there are no virtual particles exchanged inside a proton. It seems like your comment implies that, sorry if I misunderstood.
On the contrary, this means that there are too many virtual particles (gluons) being exchanged inside a proton, so many that perturbation theory is not applicable.
Virtual particles are part of an indexing scheme for perturbation series - saying that you leave the perturbative regime when you have "too many" of them is like saying that crystalline solids melt when they have too many normal modes.
Your question is can be posed as “is there a well-behaved resonance of the gluon field in a proton, that lasts long enough for it to be identified”. It's kinda like identifying a bubble in a pot of cold water vs a pot just starting to boil vs a rolling boil.
Virtual particles are also "real", and if you don't believe me, at least you have to admit that virtual photons alone lead to real energy (e.g. Casimir effect) - and it has also been stated that gluons within protons can be interpreted as "virtual"... so I'm pretty sure your comment is wrong. I'd downvote you if I could since that seems to be what the cool kids here are doing but I used up all my karma telling the truth.
There are also tons of articles that state the opposite; that virtual particles are in fact actual particles. I don't see how either interpretation is particularly relevant. Physics uses math to model reality. Every part of that model is virtual and has some correspondence with what we experience and observe and that's all that matters at the end of the day.
The physical dress is blue and black, in spite of all the articles showing how to see it as white and gold, the articles demonstrating how in theory you could have a white and gold dress look like that given the correct lighting, and the articles saying that the distinction isn't real and that all black and blue dresses are equivalent to white and gold dresses.
Depends on the definition of a particle, and 'virtual particles' aren't the same as 'real' particles. As I said above it'd be a good idea to change the name, it'd stop lots of confusion.
Be sure to click through to the "What's a Proton" article, which contains the delightful line:
> In short, atoms are to protons as a pas de deux in a delicate ballet is to a dance floor crowded with drunk twenty-somethings bouncing and flailing to a DJ.
As I understand it, the reason Feynman diagrams in quantum electrodynamics (where the primary entities are electrons and photons) can be used to calculate properties very accurately is that the electromagnetic coupling constant (1/137) results in the higher-order terms in a series eventually vanishing away to nothing, while with the strong force the coupling constant is >= 1, so the higher-order terms have to be included, leading to things like infinities (or at the very least, ratios of very large quantities with correspondingly large uncertainties).
The strong force is a bit confusing, as it binds boths quarks with the proton and neutron, as well as binding the neutrons and protons into atomic nuclei, over short ranges (accounting for the upper size limit / stability limit of the largest nuclei). Mesons are the force-carrying entity that bind the neutrons and protons together, but gluons are the force-carrying entity that bind the quarks together, as per this wiki article:
Is it the case that theoretical strong-force calculations have just hit a dead-end and there's no way out in sight, due to the coupling constant issue?
Actually there's a bit more to it than that. Coupling constants change as a function of their energy, they're called 'running coupling constants'. As a result of this phenomenon, there are domains where alpha_s is small and therefore a perturbative expansion of terms is possible. This happens at very high energies, so at the LHC we can happily calculate the higher order terms that you talk about and each successive term is a smaller contribution than the last.
Unfortunately, alpha_s is large at low energies, and by low I mean at the atomic and nuclear scale. There you are well and truly in the domain that perturbative QCD is impossible. The only option at that point is something called lattice QCD at the quark/gluon level.
I have idly wondered whether or not there could be a completely different approach to QCD from the usual perturbative techniques. I remember reading in one of Zee's books that back 80s he pointed out to Feynman that the path integral formalism that QFT is based on has no natural way to treat something as simple as a particle in a box. And an object like a proton seems to be more like a particle in a box than a free particle undergoing an interaction.
Yeah as someone who spent 4 years of his life calculating a second order term (Next-to-Next-to-Leading-Order), I have often wondered the same thing! In my original post I grossly simplified how challenging it is to calculate terms in perturbative QCD, even when in the perturbative regime. To name a few:-
* Two loop calculations are extremely challenging on an algebraic level
* You get low energy (called 'infrared red') infinities appearing at low energies. These need to cancel between all your contributing terms, and getting them to cancel is really really challenging.
* The numerical Monte Carlo approaches become extremely computationally intensive because of high dimensional integrals and numerical instability caused by point 2
It was not uncommon for calculations of single terms to involve multiple PhD students over a decade or more.
Throughout my PhD I certainly felt like something was fundamentally 'wrong' with the approach. Alas, I wasn't smart enough to rewrite the field with a whole new way of thinking so bailed instead.
There are many components to such a calculation that can be split up amongst different research groups. I won't go into detail on all of those but essentially it boils down into two main categories of components to the calculation:-
* Analytical integrals - This is a big algebraic task where you're trying to compute an equation that can be written by hand. For example, if you have 1-loop diagram [1] then the particle in the loop effectively becomes an integral over all possible momentum configurations that particle can have. One-loop is a hard problem but reasonably 'solved', 2-loops is extremely challenging.
* Numerical integrals - This is typically using Monte Carlo techniques to numerically integrate over all possible momentum configurations of the incoming and outgoing particles. Because you can have many particles, it becomes a high dimensional integral pretty quickly. Monte Carlo scales well with dimensionality, but not that well. Therefore you need serious computation power for non-trivial numerical integrals.
Added to this fact is a fun feature of these calculations that infinities spring up all over the place. You have both a numerical and analytical game of getting these guys to cancel (they do, the calculation must be finite) but it is not a straightforward task at all.
I appreciate the insight. If you happen to see this reply, how does "canceling an infinity" work. Do you just keep trying new numbers until the infinities cancel out? I guess my confusion lies at how something can take years and where the manual aspect of these calculations comes in. I've run calculations that take minutes or even hours, but it's just one of those things where you walk away and do something else and then its done. There seems to be more of a "guess and check" aspect in high energy physics that maybe I'm not grasping.
Ok so to answer your first question, you have to isolate the divergent piece of the terms. So we typically write it as an expansion in epsilson, where you have 1/e as e -> 0 (there are higher order terms, but let's keep it simple). So if we had two contributing terms*, what we should end up with is
Easy right? Only there is a problem: the different terms have different dimensional integrals. You can't just do some alebra to cancel these terms, instead what you have to do is construct something called a subtraction scheme which moves the contributions between your different integrals, such that the subtraction terms don't contribute anything to final result and cancel each other, but render the whole calculation finite. This is a by-hand crafted thing, and takes years and years to calculate properly, which is very easy to get wrong.
The complication in particle physics is actually constructing the equations and evaluating the integrals either numerically or alebraically. The algebraic calculations are extremely hard, and checking you are right is really difficult. Typically that involves two independent research groups attempting the same calculation using different approaches and checking you get the same result.
Similarly, for the numerical evaluation of the integrals you really are pushing what a computer can do to the limits. If we consider the term:-
X * (1/e - 1/e) + finite
and I'm trying to integrate this numerically, you typically put in an artifical cutoff term as you get close to the singularity. Problem is you reach the limits of floating point precision pretty quickly: asking for the difference between two massive numbers is the worst case scenario for numerical evaluation. Trying to work around these problems are really, really challenging.
* There are many more than two terms in a real calculation
How nucleons (neutrons and protons) are bound together is similar to a molecule. If they are close enough, they can 'share' their constituent quarks. You can calculate the interaction by a feynman diagram where the two nucleons exchange one quark in each direction. This is technically the same as one nucleon sending and the other absorbing a quark-antiquark pair, which is why physicists like to say that the nucleon attraction is transmitted by mesons (quark-antiquark pairs). Of course fundamentally the strong force still facilitates the whole interaction, as it's the one preventing nucleons from just falling apart into quarks.
That's the role the meson (a quark-antiquark pair particle) carries out, but I agree it's confusing. Here's a question from physics stack exchange (without any really clear answers, other than "go look up 'residual strong force'", not very helpful) that spells it out:
> "I just read somewhere that both gluons and mesons transmit the strong force, gluons between quarks inside hadrons, but mesons between nucleons. I thought that the strong force would have one field, and one associated particle, whether inside hadrons, or between nucleons"
no, you're just going wrong about it; nothing Feynman was doing was new. Except for the fact he had a nice semi-directed graph to make sense of the celestial equations and the quintuple of the time; the Dirac Sea, etc
Are we still wrongly talking about billiard balls?
I'm guessing the field interaction when a high-energy electron hits a proton is a lot more complicated than the kinetics implied by the description,
but "surprising" results are still stated in terms of features of the "particle" produced. It seems like the particle analysis is simply ignoring field interactions that are not (currently) mathematically tractable, so instead of a 3-5 quark zoo in proton, we are witnessing 3-5 types of field interactions (and don't actually know how "many" "types" there are). Is that the case?
Right? Intuitively it seems like there's some kind of vortex dynamic happening that would be better represented by something like fluid dynamics or harmonics, but we're trying to classify different kinds of ripples and eddies as "particles".
Hawking predicted low mass objects could form a black hole, and while the proton has less mass than the minimum bounds he calculated, it is extremely dense. Perhaps it's dense enough to where it's close to a micro black hole such that it "sticks together", but information can still be exchanged at its edges? If it's acting as some kind of interface between our spacetime and a gravitationally collapsed state, then this could possibly explain phenomenon like how quantum entanglement is possible, with information being exchanged across spacetime via these quasi black holes. Just my layman speculation!
That reminds me of a throwaway line in a YouTube video with Sir Roger Penrose. He insinuated that Lord Kelvin had been pushing an idea of vortices as an explanation for early evidence of atoms [1]. However, this had suffered a few blows including Rutherford's shell model of the atom alongside the lack of evidence for a suitable fluid-like substance (aether).
Now that we are more-or-less entrenched in the mathematical model of fields, I wonder if anyone is considering vortices within those fields as a possible explanation for observed behavior.
When two waves interact it's more like an elastic collision, isn't it?
From the article it wasn't clear to me if these extra high-energy particles they were seeing as fuzz in the data (which are heavier than a photon) are actually unexplained mass or a situation of conservation of energy meets special relativity (kinetic energy -> mass).
If you put enough energy into separating quarks, I'm told you get extra quarks. So an energetic system where the masses don't add up doesn't seem like an epoch defining mystery to me. So what are we missing?
> So an energetic system where the masses don't add up doesn't seem like an epoch defining mystery to me.
Bound states aren't really made of their constituents in a classical sense. A proton is a particular configuration of the quark fields (really it's more complicated than this), but not a simple sum of quark particle states. And in particular, its mass doesn't have to be the sum of the masses of particle states.
Actually the basic particle created by the creation operator for a mode is totally delocalised. Applying the field operator to get a localised particle is really an integral over many particles
For a free field, yes. But the entities we actually interact with are ... interacting. Mode expansion doesn't work here. Electrons, photons, etc. aren't really "particles" in the sense of ordinary quantum mechanics at all.
It's about 1 hour long (plus some questions) and it goes through some basic ideas of what it means for something to have mass and all the way to the Higgs mechanism.
I've never really understood the statement that "most of the mass of the proton comes from virtual particles inside it." That being the case, why isn't the mass density of space outside the proton almost as great as it is inside the proton? Is the density of virtual particles greater inside, and if so, why?
Just ignore the "virtual particles" part. Most of the mass comes from the binding energy. As in the rest masses of the individual quarks is small compared to total mass of proton.
Virtual particles themselves can always be ignored as they are not physical. They're purely a computational method in some approaches. They don't exist in others at all. And even when they are part of the method what kind they are depends. Looking at momentum space? Your virtual particles can have any position. Looking at position? Your virtual particles can have any momentum.
Alternatively: Virtual particle just means that if you have a certain kind of field, what kind of "particles" you need to sum up to get that kind of field. The field itself is the physical thing. Viewing it mathematically as sum of virtual particles is just a mathematical viewpoint.
It's not. Just like how if you push two identically charged plates towards eachother the potential energy in that system is not made of photons.
Sure you can describe the electric field in that case by a viewpoint where you sum virtual photons together to get said electric field. Whereas a non virtual photon is alltogether a different thing. You can actually describe a normal non virtual photon as a sum of virtual photons.
Point is that virtual particles are just a mathematical tool.
Actual real gluons do exist and they're analogous to the actual photon.
In case of electromagnetism the actual stuff is the electric field. With proton (so in quantum chromodynamics) it's the gluon field. It's called that because every particle has a field and every field a particle. It would be kinda like calling electric field a photon field. Same difference.
It's a bit like the "energy" in an electric capacitor. It's a property of the system's state that is related to the interactions between the particles.
In a charged capacitor, there's a lot of electrons on one side, but very few of them on the other. When you close the capacitor, suddenly you get a lot of energy out of it.
Looks like it, quarks are bound together by gluons so as you go up the energy scale and 'see' more quarks the gluon energies dominate. In fact about 99% of the Proton's mass is in the form of this binding energy.
I didn't say the binding energy is gluons, but I suppose it's more accurate to say that the binding energy of the strong nuclear force is mediated by gluons.
Saying it's made of gluons is exactly the same as saying that a charged object in electric field has it's potential energy made of photons.
It's not exactly informative nor true. Yes you can describe the electric field as sum of virtual photons but that's different to a normal photon. And even then the electric field is not the same as the potential energy. Sure it defines it but it's not the same as the potential energy of the charged object.
In case of protons it's the same. It's better to think of it as a field, which it is. Gluon in itself is "just" an excitation of that field. Just like photon is an excitation of the electric field. And the binding energy of the proton comes from the quarks interacting with the gluon field.
The reason I'm talking so much against the virtual particle viewpoint because then people will start thinking of some things whizzing about. That's not what happens. It's a field.
It's actually better to think of even the normal fermions with mass with fields, because that's what they are. It's no longer surprising that how does electron go through both slits at the same time or how all electrons are identical. Of course they are identical as there is just one electron field that has a very specific kind of excitation that propagates.
This is not some random "Look at my weird theory". It's what Quantum Field Theories are. I mostly blame bad science journalism looking at Feynman diagrams (a great mathematical tool, don't get me wrong) that has people thinking too much about virtual particles.
The quarks that are bound in a way we call a proton are held together by the strong force at a certain distance from each other - that distance is what we consider the volume of the proton, with the quarks being "inside that volume". This system of 3 quarks has some amount of potential energy, and/or some amount of kinetic energy from the relative movement of the 3 quarks. The mass of this system is then given essentially by E=mc^2, with E being this kinetic energy.
There is a very good video of a lecture by Leonard Susskind that explains why energy and mass are interchangeable in this way if you want a more in-depth explanation:
Fundamentally, "mass" is nothing other than "confined energy". Whenever you have a mechanism for confining energy (Higgs mechanism; or a force which binds and creates a bound state) the combined package has inertial "mass"; This means: It cannot move at speed of light (c), it can change its speed and it takes energy to change its speed (a "massless" particles does none of this).
The famous thought-experiment in the regard is Einstein's "photons-box": If you could confine a bunch of massless photons (which only have kinetic energy and momentum) inside a (massless) box made out of mirrors, (he argues) the combined package would have "mass", even though the constituents do not (and the emergent "mass" equals E=m c^2 !). In other words, "mass" is an emergent property of the confined ensemble. All of the forces (especially the strong force), create bound-states which are massive and are the exact analogues of this "photon-box".
So the mass of a proton (mostly) comes from the kinetic energy of its confined (by the strong force) constituents (the quarks and gluons).
>Many quarks and antiquarks seethe in a roiling particle “sea.”
What do physicists mean when they "antiquark"? I had it explained to me that it spins the opposite way. Which confused me more, what does it matter that it spins the opposite way? You means it has constructive or destructive interference? If it has destructive interference, why don't particles explode?
In a similar vein, chemistry says that chemistry bonds and antibonds [1]. I can kind get it. But not really.
The equations governing quarks admit negative energy solutions, which we interpret as antiquarks. Chemistry typically uses non-relativistic quantum mechanics which only have positive energy solutions (like classical mechanics).
The solutions in chemistry are wavefunctions. Wavefunctions give a complex number to each point in space so they may interfere constructively or destructively to give complex numbers of greater and smaller magnitude respectively. The Schrödinger equation can be solved for each atom independently to get one electron wavefunctions named atomic orbitals, and, in molecular orbital theory, these atomic combined to give molecular orbitals which are one electron wavefunctions for the molecule. When the atomic orbitals add up constructively to give a molecular orbital with a higher electron density between the atoms it's a bonding molecular orbital, otherwise it's anti-bonding.
Both quarks and anti-quarks can spin in two ways (even though this spin is not a conventional spin but something special to quantum). When a quark and an antiquark are produced, spin must be conserved, so in pair production each must have opposite spin so the total is zero.
It's interesting that the article and the animations still lean on the concept of the proton having an "inside" with some kind of boundary. It makes for interesting animations, but that's not really a good way to understand anything at the quantum level. The particles and forces that make up a proton have probabilities of having certain features like momentum and velocity, and they are more likely to be within a certain area, but there's no "inside" for a charm quark to pop out of. The measurement that finds a charm quark/antiquark pair is just showing a certain state of the system that under standard conditions has a state we call a proton.
Sort of off topic, but sometimes pondering these low-level physics questions forces me into a philosophical state of mind. It seems like asking questions about basic particles is representative of a mode of thinking that drills down ever further, trying to find some kind of conceptual bedrock. But it always seems possible to ask again, "What lies underneath this? What is the cause of this thing's existence?" In any case, it seems either that you have found the one thing that underpins everything else or you have found the collection of things that all endlessly perpetuate each other. Both of those possibilities seem somehow unsatisfactory or impossible. There must always be something else. Could it be that this conceptual craving is somehow just a side effect of how our minds are built? Or is it fundamental to reality in some way?
I don't know, but let me point the obvious: it feels very weird that fundamental things are so complicated.
Somehow I want to think that there's a much simpler layer underneath and all this imperfection comes as a second order side effect.
Plato's cave seems the relevant meme. But is it really complexity a side effect or, as you suggest, is simplicity a side effect of our minds' pattern matching preferences?
I can sympathize with this. I love discovering some generalization that subsumes all the complexity. But what if we follow this to its extreme? Suppose we find the one perfect symbol that precipitates all other concepts? What then does that symbol even do but just reflect or perturb its environment? Isn't that just like moving the goalposts? Makes me think of the concept of Kolmogorov complexity. That's the idea that the informational content of some signal is equivalent to the length of the shortest computer program that can produce it. But what interprets the program? And how complex is that thing? It's all circular. And I'm not sure there's really a way out of that. It's just an inherent feature of looking at the universe conceptually.
> is simplicity a side effect of our minds' pattern matching preferences?
That's a good point and I tend to think so. Think about this: pretty much everything (any object or property we observe) is an abstraction. People talk about people who are bad at abstracting and we know what they mean, but actually everyone is abstracting everything. Our actual experience without abstraction is just a bunch of unassociated colors and sensations and whatnot.
The thing that really matters when breaking thing apart into ever smaller things is not really if we are accessing ever deeper level of reality.
What matters is: can we use this newly discovered sub-structure to do something we couldn't before.
The answer to this was a clear and resounding "yes" when we reached the level of molecules (chemistry, which allows us to do a great many useful things), still "yes" at the level of the atom (atomic energy, transistors, etc...).
It is however unclear that QCD, quarks and inner proton structure reality level have yet produced anything usable to implement our will upon the world.
It may yet happen, but to answer your questions: once the depth we dig at stops producing anything usable by an engineer (string theory, quarks both currently fall into that bucket I think), not entirely sure the digging is philosophically valuable in any way.
I think you may have some hindsight bias here. I do not think that when chemical and atomic structures were discovered/understood that knowledge was immediately put to use. Nuclear physics dates back to the late 1800s, it wasn't until the 1940's where that knowledge was put to practical use. I wouldn't expect anything different with QCD. In fact, I would expect it to take significantly longer to develop practical applications of the theory given how much more complex it is.
I think your reply gets at the answer to my own question that I tend to lean towards. And that is that craving further concepts is an inherent problem that follows from being a thinking being. What you say seems like part of the answer, which is that one needs to make a conscious decision not to be bothered by the fundamental lack of a justification for reality. Just focus on what your knowledge enables you to do. But it still seems sad on some level that we're "condemned" to coast through this world that is so rich in detail but seemingly lacking in purpose.
That's actually specifically why I mentioned transistors.
However, I don't believe QCD has yet produced anything tangibly usable to do stuff in the world.
The proof is in the pudding: if QCD ever does produce something useful, I'll happily recant.
But my general point was that as we dig deeper and deeper, what we get is exponentially diminishing returns, up and until the point when we'll research stuff that's maybe logically coherent, intellectually satisfying but plainly useless, just like string theory currently seems to be.
My point was that when quantum mechanics first was proposed early last century, I can’t imagine anyone would have even considered LEDs as a thing even in their wildest dreams, yet it was obvious once further progress occurred, and was key in understanding and developing them past the initial ‘that’s odd….’ stages.
We don’t know yet if something similar will come out of QCD (understandable and usable ‘high temperature’ superconductors? Quark matter computers? Super high strength materiel derived from some kind of degenerate matter?) but it definitely seems less likely by the day.
It does at least have falsifiable predictions, so it’s about a billion miles ahead of string theory!
It’s also possible we’ll need another 50 years of engineering or a world war (I hope not) to dig deep enough into areas to discover another, simpler, way to think about it that is more useful.
> Very limiting to couple the pursuit of knowledge to application
Didn't say that either.
I said "useful", and what I meant was "can the knowledge gained be used by us to implement change now or at some point in the future".
As pointed out by another poster, the interesting talking point is that it is hard to guess beforehand whether knowledge gained will ever be useful.
I nevertheless believe in the principle that research should be directed by the hope of discovering something useful, not by the mere pleasure of finding some sort of satisfying "explanation" to the way things work.
But hey, if mine does satisfy you, please let us know what criteria you would use to discover when you've squarely left the area of worthy research to enter that of intellectual onanism.
There are books on the topic e.g.,
"The End Of Physics" by D.Lindley.
There are two questions:
- whether there are laws that describe everything there is to know (e.g., the answer is yes for chess—there are rules that describe it). It is the "fundamental" dimension (particle physics at the moment)
- whether there is something to do once we know all the laws. The answer is yes ("knowing rules do not make you a grandmaster") e.g., we likely know all of the fundamental physics required for turbulence or brains but it doesn't solve these fields (there are interesting unresolved problems). It is the "applications" dimension.
The never-ending chain has bothered me too. I realized that if there is a theory of everything, it needs to prove itself. As far as I know, that’s a logical contradiction. Maybe resolving that contradiction is the door to moving forward. Is the concept of a “theory of everything” invalid? Is modern logic insufficient to find it?
There seems to be an unspoken assumption that all protons (as in: a set things that seem to have similar external properties and behaviors) are actually identical "inside" or - to put it another way - all "built" the same way.
Other than Occam's razor, why is that assumption considered valid?
Have we verified this experimentally?
Or does some complex piece of math show that only one possible internal structure can lead to similar externally observable behaviors?
The energy levels of individual atoms have been compared at the level of a few parts in 1E18 in optical atomic clocks. If properties of the protons making up the nuclei of these atoms (mass, charge,...) were different at that level, it would have shown up.
My main takeaway from Quantum Field theory in grad school was that the proton (and electron, etc really all subatomic particles) is just a useful fiction; much like a spherical, frictionless cow. It's just that in particle accelerators where it breaks down so it's a quite useful fiction. Renormalization[1] in field theory is really trippy...
We call a particular configuration of 3 particular kinds of quark "a proton", and another one "a neutron" (there are also anti-protons). In general, combinations of an odd number of quarks (3, 5, 7, ...) are called baryons (only combinations of 3 and 5 have been proven to exist, any more are only speculation). There are also some unstable but observable combinations of equal numbers of quarks, which are collectively called mesons (combinations of 2 and 4 quarks have been proven to exist, others are only speculated).
Now, why are the combinations of 3 quarks the only ones (that we know of, at least) that are stable is a much more complicated question related to properties of the strong force.
I'm not smart enough to answer this, but it seems to me that the question is along the lines of, "Why do all verbs describe action?" Because if they were different, they'd be something else.
I don’t think this is necessarily new. On the level of fields the universe is not nice little particles or waves in neat groups in a vacuum. It’s a roaring, swirling turbulent ocean. Yes what we call a proton is still a particular configuration, but it’s not existing in a vacuum, it can entangle with other stuff. When we do some experiment it’s like trying to pick a particular wave out of the ocean. Seeing a charm anti charm pair popping up sometimes shouldn’t really be a surprise.
There’s nothing wrong with the 3 quark description of a proton, it’s a model, it’s useful up to a certain level of accuracy.
I don't think it is, I think this is just a popsci article on that well-known (in the field) fact.
I don't want to make it sound easy, because as the article says, our math lacks the ability to handle the way our current best theories describe it, but it certainly isn't any easier trying to understand QCD through the lens of particles as the fundamental objects. It's really a mess of field fluctuations, and in those field fluctuations we have certain patterns we call "particles", but those patterns can shift and ebb and flow in any number of ways, including in ways we have no intuitions for since our macroscopic intuition keeps wanting to sneak particles in the backdoor despite everything being waves.
Directly understanding what's going on isn't easy, but it's probably still easier than trying to hold on to particle-based ideas.
Or, you know, since none of this matters on a day-by-day basis to hardly anyone, I think just looking at it from the particle point of view and calling it a day is a perfectly viable option. In which case, a proton is three quarks, full stop. It's not 100% correct, but hey, QCD isn't either (still waiting on that Grand Unified Theory), so there's no real harm in stopping at the 3-quark model.
> but hey, QCD isn't either (still waiting on that Grand Unified Theory)
Note that there may well not exist any GUT. However, QCD can't be correct until it also accounts for gravitational effect, so what we're waiting for is a theory of Quantum Gravity that is consistent with both QCD and General Relativity.
The universe runs on some principle. It may not be accessible to us, either for inability to gather the data, inability to represent it in our heads, or sheer staggering complexity, but there is some unified theory.
A GUT would be a theory in which a single fundamental force/interaction exists - one that unifies the electro-magnetic interaction with the weak interactions*, and the strong interaction, and perhaps with gravity. But there is no reason why the universe shouldn't have 3 or 4 different fundamental interactions.
In contrast, QM/QFT can't deal with particles curbing space-time, and GR can't explain the movement of elementary particles, so we know for sure those two theories can't be completely correct: there must exist something we're missing to explain how gravity works at the lowest detail level.
* these are already unified to some extent as the electro-weak interaction, which as I understand is believed to be a single kind of interaction at very high energy levels, as seen in the early universe, with 2 different aspects at the lower energies typical of our age. I may be wrong on some of the details here though.
Actually the concepts are perfectly explained by plenty of people who, you know, actually know. Read the other links in this thread. But please downvote me some more. It's obvious you're not arguing reasonably because you're clearly leaving out the fact that the terms in all these relevant equations are associated with physical components that we talk about WITH WORDS
Like mass
and charge
and energy
and probability
If you know the math you can share it here and say what the terms mean
If you dont know the math then your comment contains the lie that you know what you're talking about and that people should listen to you
The way to express "cosine squared" in words, without including "cosine" or "squared", would be a lesson in cosines and a lesson in squaring. So you're correct, but why is this point useful?
using your example only, those are words which mean something geometrically and relationally. they are functions for numerical computation of those relationships. they dont describe physical systems that we're all talking about originally. if you show me some QM math about some experiment I will tell you what it means. why is everyone so confused about this? that's one thing here i cant understand easily. it's amazing. first they say we cant use words at all. then they say theyre hardly explainable with words. my
mistake earlier was not simply retorting with the question of what % the things are explainable with words and not. mind blowing.
Because, interpreted strictly, what you're insisting is trivially true. Obviously anything can be explained with words. However, sometimes the volume of words required would make the explanation incredibly tedious, and words aren't the most appropriate language.
English/natural language isn't a privileged mode. It's one of many, including math, musical notation, computer code, and chess notation. We use the best language for the context, and who cares that laborious translations are available to others? I could be typing ascii codes in binary, instead of letters right now, but so what?
i stopped reading after your first paragraph. you are doing nothing but insisting on your opinion. language and concepts are compressable and often easily abstracted. just give us an example of something that requires me to talk to you only in math expressions instead of concepts in english and maybe i'll concede the point but i said many times now i already have been proven right by the single example of the plain english description of a nonzero amount of the principle behind something otherwise called "the most complicated concept". that must amount to a supposedly inordinate quantity of complexity described plainly. qed. the real question is why we are having so much trouble agreeing. take care
no, I'm pretty sure that my defending the senseless subjugation of people who tell the truth is much more important than my avoiding a little bit of stress. after the ridiculous life that I've had to live, I'd rather die 20 years too early then not have a conscience.
1.) You're talking about a nested comment on a hacker news post. A little perspective is helpful.
2.) You are making grandiose and uncharitable assumptions about the interpretations of things other people said, e.g. equating not having the words to to describe something to implying that we should give up trying to understand it more.
3.) Having a physical definition for every term in an equation does not mean the resulting behavior/phenomenon can be conceptually explained with words. Can you conceptually explain what "spin" is for an electron?
3. For starters, the math does not explain "what spin is". So you've introduced a fallacy off the bat, and I suspect it was intentional. But if you tell me how you know about spin then I will explain it conceptually. It's not so complicated. None of this proves anything though. What's the fallacy called? I dont remember.
And I guess you're going to invoke some vague connection to angular momentum to do so? We're talking about empirically derived properties. The math certainly predicts the empirical results but it does not give an accurate conceptual connection to concepts that we, as humans living and interacting with a classical world, can actually understand.
edit to add a bit more: I should also point out that no one introduced a fallacy except you. You are, yet again, stretching other peoples words to build straw man arguments for yourself. I don't remember ever making the claim that the math explains ""what spin is"".
we dont live in a classical world, noob. things tend to decohere and mix at this scale but quantum phenomena are obviously observable. and no, you're the one arguing in bad faith. this discussion was about whether these mathematically modelable concepts can be explained by a knowing person with words. not whether i can magically explain something you dont even have math for. go away and find something productive for your life instead of attaching yourself to discussions to feel more alive.
"Can you conceptually explain what "spin" is for an electron?"
> You are really an unpleasant person to interact with.
I'm sure Meletus felt that way while Socrates was absolutely wrecking him in court and exposing his hypocrisy. Maybe that's why they murdered Socrates?
You are not qualified to take part in the debate I raised. It's obvious you dont understand the little physics you have read nor know the math you're trying to talk about. You should count yourself lucky instead because this conversation is a chance for you to open your eyes to a world of physics which is even more amazing than you realized. Instead you'll probably just keep trolling. 'The starting point of true learning is the realization that you're not actually aware of anything yet.'
> let me know next time you personally observe a quantum phenomenon with your own senses.
to my knowledge, literally every single "sense" measurement is a "quantum" phenomenon which happens via entanglement along with literally everything else at all scales. you still have insufficient understanding of this.
and dont mince words about quantum being a theory and things being beyond theory. you contradict yourself in that way and if consciousness is beyond our science now and that is your point then I invite you to stop arguing with me and will remind you that we are discussing experiments in real life and what physics means, not what I feel in my heart.
I remember when I had delusions of grandeur in my mother's basement as well. I'm sure in your mind you're "absolutely wrecking" every person you attack online. As stated by a previous commenter, you should probably spend less time on the internet inventing straw men to "absolutely wreck".
as long as you do not discard your preconceptions and delusional words then you are going to misunderstand that what is being opposed or destroyed while you are being freely educated and benefited is you. just forget about me and go read about entanglement and measurement.
They are bringing more and more energetic electrons into the proton and of course it supplies the energy budget to show them more exotic virtual particles inside the proton and more gluons. Hit something in the proton, get a shower of sparks.
"What we observe is not nature itself but nature exposed to our method of questioning.” — Werner Heisenberg, Physics and Philosophy: The Revolution in Modern Science (1958)
That's usually how history works. An abstract definition of progress is the accumulation of cultural knowledge that informs the next generation of past mistakes and errors. I don't know much about Aristotle but I'd guess he was probably wrong about a lot of things given his historical time period.
In the last couple years I've dropped our node_modules directory size down by half, and I'm still disgusted both with the state of it and how much work I put into accomplishing that.
The moral of too many of my stories is if something is bothering you, track it first before trying to fix it. Because it's easier to get other people to help police a graph than a series of unix commands. And for everyone else you'll get regressions when you're focused on some other priority. Data points like "sometime in the last month" are pretty hard to nail down on a large codebase, especially if it's not a monolith. Last Tuesday around noon is pretty specific.
Is the "charm quark is heavier than proton" thing the usual situation where the author conflates the mass of the particle with the mass of the particle plus the mass of the field associated with a free particle? Every system is lighter than its constituent particles in this sense, but sometimes people make a big deal about it, usually when the binding energy is high (i.e. the mass difference is large).
Personally I think it's because we're "looking" at it from the wrong angle. A bit like in programming when you're stuck and you need to take a step back and approach the problem differently. IMHO the fundamental construct is probably something way more abstract, i.e. "information", with some laws that we aren't even aware of yet that will probably challenge the principle of locality.
This. It’s bad philosophy. Non local, non physical, these are the concepts to get comfortable with before attempting to understand the quantum in a coherent way, unless understanding the nature of physicality and locality isn’t your goal. Looking at the quantum world as a bunch of tiny objects will only lead to an infinite regression, where new even smaller objects are continuously discovered.
than most of our brains represent, perhaps ... but clearly there are people who see things others don't ... give them the ability to see at these scales, and enough explanatory skills, and perhaps it will become something even a child can understand.
Indeed, it’s an uncomfortable idea but maybe someday we’ll have to accept it. That we don’t know, we’ll never know, we can’t know. I wonder if we’ll be able to prove that we can’t know something. Or prove that we can’t prove it.
Or, alternatively, the human brain, unlike dog’s, has the capability to learn (and eventually understand) that may already exceed what is needed to understand all there is to understand.
I don’t believe that would be referred to as “the proton” unless it was being called “the proton compatibility layer”. It’s important not to forget the colloquial meanings of words :)
people make grammatical mistakes often enough when typing that you kind of need to parse sentences in the way that makes the most sense. this sometimes means parsing correct grammar as a mistake because the fixed version makes perfect sense. then you read the article and laugh at yourself because yep, both kinds of proton are quite complicated.
You assume we exist. DonHopkins effectively assumes we don't exist, so reaches an opposite conclusion
On just cause ;), cyclical explanations create a giant hamster wheel. Why the wheel at all? So I think he implies the need for a prime mover. I.e. a force outside the system that defines the system. Kinda like axioms are needed to make maths work
Why would I complicate things by assuming otherwise? In any case, it seems like a small thing to ask of a diety to at least be capable of manifesting that way.
I demand it, really. Why should I put any stock in a god who can't explain (1) where they came from and (2) what endows them with any authority? It's a very low bar for entry.
"Just Cause" was certainly not intended by Bush or his minions to be a pun. Remember, this is the same family that gave us "Mission Accomplished".
Conservatives aren't known for their sense of humor, which is usually limited to punching down and demeaning weaker opponents, not insightful self depreciation and candor. Case in point:
The "Just 'Cuz" interpretation was pointed out by critics of Bush's otherwise unjustifiable invasion. The US created the original problem by supporting and paying Noriega while turning a blind eye to his abuses and corruption for so long.
The operation plan it came from was called the "Prayer Book", so circular reasoning was the essential justification of its self fulfilling prophecy, just like with any religion.
>Operation plans directed against Panama evolved from plans designed to defend the Panama Canal. They became more aggressive as the situation between the two nations deteriorated. The Prayer Book series of plans included rehearsals for a possible clash (Operation Purple Storm) and missions to secure U.S. sites (Operation Bushmaster).
>Eventually, these plans became Operation Blue Spoon which was then, in order to sustain the perceived legitimacy of the invasion throughout the operation, renamed by the Pentagon to Operation Just Cause. General Colin Powell said that he liked the name because "even our severest critics would have to utter 'Just Cause' while denouncing us." Critics, however, renamed it Operation "Just 'Cuz", arguing that it had been undertaken "just [be]cause Bush felt like it."
>The incursion into Panama, which came to be derisively known as “Operation Just ‘Cuz,” is the hardest to justify on Realist grounds. The rationale for going in doesn’t stand up to the test of time but made some sense at the time. The Panama Canal was indeed a longstanding American interest. And the war on drugs angle was important, as was the the complicated relationship with Noriega. Regardless, we certainly didn’t go in to make Panama more safe for democracy. Nor did we stay for years nation-building. It was a limited incursion, over in less time than an NBA postseason.
>The US reaction was swift and unrelenting. In the first hour of December 20, 1989, Panama City was attacked by aircraft, tanks and 26,000 US troops in ‘Operation Just Cause,’ though the US media often labeled it ‘Operation "Just 'cuz."’ Although the stated intention of the invasion was to bring Noriega to justice and create a democracy, it left more than 2000 civilians dead and tens of thousands homeless, and destroyed entire tracts of Panama City.
I agree. I believe that the infinite engineering prowess observed in the proton and so many other aspects of creation (Like the eye! Wow!) point directly to the existence of God.
But then again, I've never met anyone who became a believer through observing creation. Just as my confirmation bias leads me to see God in these stories, I imagine unbelievers tend to receive confirmation of the absence of God.
> imagine unbelievers tend to receive confirmation of the absence of God
Another interesting question to ponder though: Who's fault is this? Is it God for not jumping out of the shadows screaming "I am he, worship me!"? Or is it an unbeliever who makes assumptions about how a God would act, and finds there is no God because he doesn't fit the unbeliever's assumptions? In which case, what is the unbeliever but a God himself?
Well you believe in the absence of Zeus, don't you? Then why doesn't that make you an atheist? (Hint: it does, since you're atheistic about a hell of a lot more Gods than any you might choose to believe in. So you're at least 99.99% atheist, or 100% atheist as the number of Gods goes to infinity.)
You believe your argument don't you? But how can you, when there is such an infinity of arguments you don't believe in?
This is word chopping, not an interesting philosophical argument. Truth is exclusionary, and the space of excluded hypotheses is at a minimum exponentially larger than the non-excluded ones, if not super-exponentially, if not some variety of simply infinitely larger, depending on how you count. Appealing to the size of the universe of false statements and/or "things you don't believe" is not meaningful.
No? Atheist literally is A-Theist, similar to amoral being A-Moral ("a" being a common prefix for "anti" or "opposite"). A-Theist means one does not believe Theism, the "belief in the existence of a supreme being or deities."
In which case, by believing in one specific God, one is not an atheist in any sense toward other religions. Believing in one specific God literally means that you do have "belief in the existence of a supreme being or deities," your only dispute is to which one.
Note that a- is a different prefix than anti-. a- means "without", whereas anti- means "the opposite of". So, being a-theistic means that you are "without god(s)". Being anti-theistic would meant that you oppose god(s). An amoral thing is a thing to which morality doesn't apply (for example, weather phenomena are amoral). Anti-moral would mean something that is opposed to morality, which would probably make it immoral (such as a human killing another human that hasn't wronged them in any way).
This is to be expected, though. Given that there is an infinite number of possible things that could have existed, it is natural that they all had very low to infinitesimal probabilities to begin with.
You don't need an "external cause". You would still have the same trouble of explaining that. You only need many attempts, same as with evolution. Life in space can be explained with Anthropic principle
This fits the pattern of discussion I often see about the anthropic principle. Someone (I'll label them the "Creationist", though it could just as well be an advocate of intelligent design) asserts that the probability of things "just happening" is vanishingly small. Sometimes the Creationist cites some generally-accepted science, and sometimes does a probability calculation, resulting in a very small probability that things happened by purely naturalistic means.
Someone else (call them the "Evolutionist") responds with the anthropic principle - that, if no intelligent life had arisen in this universe, there would be nobody here to observe that there was no intelligent life. And this is completely logically correct. It is also irrelevant. The Creationist never asserted that it was improbable that life arose in this universe, but rather that it was improbable that it arose purely by naturalistic means. The question isn't whether we're here; the question is how or why.
The Creationist was saying, either we're here by purely naturalistic, evolutionary means, with some probability (call that Pe), or by being created, with some probability (call that Pc). As far as I can see, Pc is unknowable, even in principle. But the Creationist argument is that Pe is so low that it seems reasonable that Pc is higher. That is, it seems reasonable to suppose that we are here due to creation, not just evolution.
The anthropic principle doesn't answer that argument at all. It gives an argument about "whether", not about "how".
Or to put it in different terms: The anthropic principle says something like, if there are a billion universes, and life only arose in a thousand of them, we have to be in one of those thousand to be having this conversation. (Note that I don't actually believe in multiple universes; this is just to make the probability discussion clearer.) But the Creationist never denied that. The Creationist says: Of those thousand universes, if life arose by creation in 998 of them and by evolution in only 2 of them, it seems reasonable to suppose that we're in a universe where life originated by creation, not evolution. The anthropic principle, which asserts that we're in one of the thousand, doesn't address the Creationist's argument at all.
Unless.
It seems to me that everyone who pulls out the anthropic principle in this situation implicitly assumes that Pc is precisely zero. They never explicitly state this assumption, but I think it's there in their thinking. So for the Evolutionist in this conversation, Pe and the probability of life at all are exactly the same, and the anthropic principle does address the actual claim.
But, instead of being irrelevant, in this case the anthropic principle is begging the question. The Evolutionist starts with the conclusion that they are arguing for. That's invalid logic. That's so invalid that, to the degree that the Evolutionist relies on the anthropic principle to support their position, to that degree they should doubt their position.
(I think the Evolutionist pulls out the anthropic principle for an additional reason - it's easy. It lets them "win" the discussion without having to disprove the Creationist's big scary probability number.)
I distinctly remember being 6 or 7 drifting to sleep one night and suddenly visualising what it would be like if there existed nothing at all, not even empty space but nothing, no Universe and nothing ever happening ever or anywhere. It was terrifying.
It was about the same time that a family member had died so I was coming to terms with the fear of dying for the first time, so I guess that's what triggered this.
The 'Existing' article is the one to blame... 'Philosophy' is there as the second term, but 'reality' is the first term and that one takes you on a pretty long detour
"Please don't complain about tangential annoyances—things like article or website formats, name collisions, or back-button breakage. They're too common to be interesting."
A proton contains an entire universe on its own, and our universe itself is a proton. You will never reach the end of its depth as it will reveal just another nesting level, until you hit the level where one would require more than all of the universe's energy in existence to reveal it.
Hence, reality cannot be understood, by design. Reality is chaos, meaning and stability mere perception.
> The proton is a quantum mechanical object that exists as a haze of probabilities until an experiment forces it to take a concrete form
I don't necessarily subscribe to the 'simulation' viewpoint, but that sounds exactly how some lazy evaluation/procedural generation system would work. Don't need to compute values until they are needed. Just like atomic orbitals.
Add that to all the quantization we have discovered in nature, the speed of light limit (which is also the speed at which information can be transmitted), the time dilation effects with speed... and that provides plenty of food for thought.
https://profmattstrassler.com/2022/09/09/protons-and-charm-q...
Virtual particles do not necessarily have an invariant mass. That's why you can find examples of typically huge particles inside protons. That's why a beta decay of a neutron can involve the production of a virtual W- boson that has an invariant mass that's 86 times more massive than the neutron.