What Is a Particle?(quantamagazine.org)
quantamagazine.org
What Is a Particle?
https://www.quantamagazine.org/what-is-a-particle-20201112/
41 comments
What a refreshingly honest answer from such a rigorous article: “We don’t know”
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For all we know about physics, we still can't answer basic questions.
Much of physics is just describing how our world behaves, not what our world is.
To me, It's depressing that all the physics we know could be thrown away with one discovery.
As a lay person, it seems useless to spend too much time learning what we currently know.
It's like becoming well-read on the latest theories of copernicus only to have Isaac Newton blow the whole thing up.
It's great if you're a physicist. It opens doors to new work.
But not so great if you just want to know what it is and how does it work.
Much of physics is just describing how our world behaves, not what our world is.
To me, It's depressing that all the physics we know could be thrown away with one discovery.
As a lay person, it seems useless to spend too much time learning what we currently know.
It's like becoming well-read on the latest theories of copernicus only to have Isaac Newton blow the whole thing up.
It's great if you're a physicist. It opens doors to new work.
But not so great if you just want to know what it is and how does it work.
Once we know how things work with clarity, don't they become boring and lose some of that wonder?
I think most physicists would be thrilled if we discovered something genuinely new and fundamental that forced us to reevaluate all our existing models.
It hasn't happened in a while, though.
It hasn't happened in a while, though.
It’s not that bad... in fact, quite the opposite :-)
Whenever we peel back a layer to discover new physics, the old models are never lost, since the new models must necessarily reduce to those in more familiar situations!
Another factor is that as we learn more physics, as important as it might be to find answers, it is even more important to understand how our previous questions/notions might have been naive, and what might be better concepts with which to formulate our models. The variety of perspectives on the meaning of a “particle” merely illustrate that fact, applied to a naive word/concept that we’ve strung along for a long time.
Whenever we peel back a layer to discover new physics, the old models are never lost, since the new models must necessarily reduce to those in more familiar situations!
Another factor is that as we learn more physics, as important as it might be to find answers, it is even more important to understand how our previous questions/notions might have been naive, and what might be better concepts with which to formulate our models. The variety of perspectives on the meaning of a “particle” merely illustrate that fact, applied to a naive word/concept that we’ve strung along for a long time.
I'm not a professional physicist but it would seem unlikely that one discovery would permanently wipe generations of fruitful knowledge and imagination which has passed the eyes of some of the most brilliant minds that ever walked the planet. Not to say that it can't happen, but it would be more likely that we are missing a component/relationship that we don't understand about our reality either because we don't have to the physical senses to detect it or the technology to measure it. I'd highly consider studying some physics even if you view yourself as a layman, it can geniunely be immense fun!
>“That entire semester I didn’t learn a single thing from the course,” said Van Raamsdon
Oh, physics grad school, never change.
Oh, physics grad school, never change.
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I loved this article!
In the following HN article:
https://news.ycombinator.com/item?id=24131831
The author (somewhat of a crackpot!) writes:
>"In classical physics, you have the particle/wave duality. Basically, one is the other, depending on frame of reference.
That particle wave duality (I've determined) is actually a particle/wave/field TRINITY.
That is, particles ARE waves (depending on how you look at them), waves are particles (depending on how you look at them), BUT ALSO waves are fields (depending on how you look at them), and fields are waves (depending on how you look at them), and fields are particles (depending on how you look at them) and particles are fields, again, "depending on how you look at them".
Google "Starlings". A single starling at rest is a particle, in motion, it's a wave, and many of them together moving in unision, that's a field.
Also (and this is the advanced lesson), you can have various degrees of recursion in this, for example, a whole field of starlings could be viewed as a single particle, then that could comprise multiple particles if teamed up with other fields of starlings, and then those things could move like wave.
Think nested particles/waves/fields -- inside of other particles/waves/fields.
Also, the smallest unit of space (to implement all of the others), DOESN'T NEED TO PHYSICALLY MOVE; that is, it only needs to state-change, like a pixel, if it were a magnet, it could change from a North Pole to South Pole (or possibly neutral), if charged, the charge could go from positive to negative and back, if a region of force, the force could push one way and then the reverse, etc., etc."
PDS: I don't know; but the author of that post sounds like a crackpot, and pretty delusional to me...
(Oh, wait a second... I'm the author of that post! <g>)
(I resemble that remark! Doh! <g>)
https://news.ycombinator.com/item?id=24131831
The author (somewhat of a crackpot!) writes:
>"In classical physics, you have the particle/wave duality. Basically, one is the other, depending on frame of reference.
That particle wave duality (I've determined) is actually a particle/wave/field TRINITY.
That is, particles ARE waves (depending on how you look at them), waves are particles (depending on how you look at them), BUT ALSO waves are fields (depending on how you look at them), and fields are waves (depending on how you look at them), and fields are particles (depending on how you look at them) and particles are fields, again, "depending on how you look at them".
Google "Starlings". A single starling at rest is a particle, in motion, it's a wave, and many of them together moving in unision, that's a field.
Also (and this is the advanced lesson), you can have various degrees of recursion in this, for example, a whole field of starlings could be viewed as a single particle, then that could comprise multiple particles if teamed up with other fields of starlings, and then those things could move like wave.
Think nested particles/waves/fields -- inside of other particles/waves/fields.
Also, the smallest unit of space (to implement all of the others), DOESN'T NEED TO PHYSICALLY MOVE; that is, it only needs to state-change, like a pixel, if it were a magnet, it could change from a North Pole to South Pole (or possibly neutral), if charged, the charge could go from positive to negative and back, if a region of force, the force could push one way and then the reverse, etc., etc."
PDS: I don't know; but the author of that post sounds like a crackpot, and pretty delusional to me...
(Oh, wait a second... I'm the author of that post! <g>)
(I resemble that remark! Doh! <g>)
It's like a wave, but different.
A collection of ripples throughout a bunch of seas stacked on each other.
To avoid philosophical contradictions, at least in respect to phenomenology in the transcendental aesthetic, particles in this sense must be an association of measurable properties (mass, magnetism, charge, etc.) extended in space (and therefore time by the nature of "measure").
Of course there is the other sense of particles in metaphysical domains, such as the 'holes' in semiconductor physics, which cannot be directly measured but can be implied
Of course there is the other sense of particles in metaphysical domains, such as the 'holes' in semiconductor physics, which cannot be directly measured but can be implied
in QED there are really only fields and subsets of those fields that have the label 'particle'; I'm not sure how your metaphysics of properties/extensions maps onto a smooth continuous manifold such as that.
The article tackles and refutes this pure field view, but continuous manifolds are no issue, and is required for anything to be extended in space--the transcendental aesthetic refutes the type of discursive space you're presuming, such as that of Leibniz.
Or to quote yourself: "Anytime someone insists on HN that virtual particles are real, you can just tell them that Arkani-Hamed disagrees with you and that he is also smarter than you."
Or to quote yourself: "Anytime someone insists on HN that virtual particles are real, you can just tell them that Arkani-Hamed disagrees with you and that he is also smarter than you."
> Arkani-Hamed, a leader of the effort, called quantum fields “a convenient fiction.” “In physics very often we slip into a mistake of reifying a formalism,” he said. “We start slipping into the language of saying that it’s the quantum fields that are real, and particles are excitations. We talk about virtual particles, all this stuff — but it doesn’t go click, click, click in anyone’s detector.”
There you go. Anytime someone insists on HN that virtual particles are real, you can just tell them that Arkani-Hamed disagrees with you and that he is also smarter than you.
There you go. Anytime someone insists on HN that virtual particles are real, you can just tell them that Arkani-Hamed disagrees with you and that he is also smarter than you.
Science is split in two: 1) It is about concrete observations 2) It also hypotheses about potentials. These parts are distinct processes, but also complementary. Both are important for science to be practical and useful. It is always important to be explicit which part of scientific method is under focus, as human minds can only focus one thing at a time.
If elements of the universe have probabilistic distributions until observed, you have also a dualism there: 1) the observable element 2) the probabilistic structure surrounding it. Both are mystical and interdependent.
Maybe the particle and observation seems more real, but they both adhere to structure that surrounds and shapes them fully too. What we observe though is not particles themselves, but after-effects of the fleeting mirage. So everything is a copy, thus holographic nature.
If elements of the universe have probabilistic distributions until observed, you have also a dualism there: 1) the observable element 2) the probabilistic structure surrounding it. Both are mystical and interdependent.
Maybe the particle and observation seems more real, but they both adhere to structure that surrounds and shapes them fully too. What we observe though is not particles themselves, but after-effects of the fleeting mirage. So everything is a copy, thus holographic nature.
> Anytime someone insists on HN that virtual particles are real, you can just tell them that Arkani-Hamed disagrees with you and that he is also smarter than you.
So, argument from authority then?
Are all experts in agreement on virtual particles? If not, which are we meant to 'follow'?
And BTW, I have no position on virtual particles.
So, argument from authority then?
Are all experts in agreement on virtual particles? If not, which are we meant to 'follow'?
And BTW, I have no position on virtual particles.
Arguments from authority are only an issue if the one at the receiving side of them could reason about the topic themselves and are discouraged to actually do that because of the argument.
did you miss the bit where I said:
> Are all experts in agreement on virtual particles? If not, which are we meant to 'follow'?
?
the person I was responding to picked out one particular expert's view
"you can just tell them that Arkani-Hamed disagrees with you and that he is also smarter than you."
aside from the silly "he is also smarter than you", just because one expert holds a view doesn't make it right.
If all the experts were unanimous, and the particular point had been well tested, then a point like yours would hold.
Also, the comment I was responding to was assuming that no-one on HN has a relevant background for having a solid opinion on virtual particles. I certainly don't, but I would not make that assumption about everyone on this forum. I don't agree with the notion that just because someone has a high status in a field that this automatically makes their opinions superior to other people in that field.
> Are all experts in agreement on virtual particles? If not, which are we meant to 'follow'?
?
the person I was responding to picked out one particular expert's view
"you can just tell them that Arkani-Hamed disagrees with you and that he is also smarter than you."
aside from the silly "he is also smarter than you", just because one expert holds a view doesn't make it right.
If all the experts were unanimous, and the particular point had been well tested, then a point like yours would hold.
Also, the comment I was responding to was assuming that no-one on HN has a relevant background for having a solid opinion on virtual particles. I certainly don't, but I would not make that assumption about everyone on this forum. I don't agree with the notion that just because someone has a high status in a field that this automatically makes their opinions superior to other people in that field.
All "arguments from authority" are breaking these rules. If they didn't, they wouldn't be "arguments from authority". They would be much stronger claims that can stand on their own.
Feynman was asked in a seminar why the individual terms of the pertubation expansion have meaning. Basically he cannot fathom the question and his (correct) answer is only the whole sum has a meaning. From 10:00 onwards, quite interesting, https://www.youtube.com/watch?v=72us6pnbEvE&list=PLYuIDo1vZp...
Of course virtual particles are only present in the individual terms of the pertubation expansion, so their reality is as iffy.
Whether or not they are real is more a philosophical issue than a physical one. While we should presumably take seriously everything this Arkani-Hamed character has to say on physical issues, on philosophical issues this is much less clear. Everybody can have his/her opinion on these. And since we seem to like to talk out of authority here you can say that a PhD in particle physics told you. I am no longer in that field now anymore, though. So maybe I am indeed more stupid.....
Not my field at all so please be forgiving if I mix this up, but aren't virtual particles a possible explanation of the Casimir effect (https://math.ucr.edu/home/baez/physics/Quantum/casimir.html)?
There are different explanations, but the original one (zero-point energy) is very heuristic, involving operations with infinity. There are more physical explanations in terms of physical EM interactions (van der Waals forces), see https://arxiv.org/pdf/hep-th/0503158.pdf
The problem with that is that he's a physicist and not an ontologist, so that's not a partciularly strong appeal to authority.
well, physics can be viewed as branch of ontology, I guess everything is a branch of ontology.
I'd say that "everything is a branch of physics" is an easier argument to sustain!
Good, now explain the electron self-energy and the Casimir effect without that
Has anybody ever said they were real? The word "virtual" seems to imply that whoever is using the term should know they are not. They're just convenient mathematical artifacts.
Guilty as charged. I guess I do not see the difference between convenient mathematical artifact and "real". But I am also a Greg Egan fan, so no surprise there.
Although people usually do not get hung up on the virtual particles. Rather people get annoyed when we say that the definition of a "particle" is "excitation of a quantum field".
Although people usually do not get hung up on the virtual particles. Rather people get annoyed when we say that the definition of a "particle" is "excitation of a quantum field".
Equal doesn't mean idential.
You have an apple in one hand. Since
I think that a lot of confusion arises because of the innocuous seeming equal sign. Explicitly replace the equals by approprate (algebraic) maps, and at least for me, the relationship becomes a lot clearer.
Maybe more familiar to HN, maybe it helps to do "typed" math? E.g. counting numbers have a different type than equivalence classes of Cauchy sequences. From a set theory perspective, it makes sense to ask the question whether the number 3 (as a set) equals the collection of triangles in R^3 (as a set). Of course, the two aren't equal, but it seems weird to even ask this question.
Maybe it should be just as incongruous to say that some vacuum state equals it's decomposition into virtual particles. The two things are just differently-typed. You need some computation to convert between them.
You have an apple in one hand. Since
1 = 1/2 + 1/4 + ... + 1/2^n + ...
I think that a lot of confusion arises because of the innocuous seeming equal sign. Explicitly replace the equals by approprate (algebraic) maps, and at least for me, the relationship becomes a lot clearer.
Maybe more familiar to HN, maybe it helps to do "typed" math? E.g. counting numbers have a different type than equivalence classes of Cauchy sequences. From a set theory perspective, it makes sense to ask the question whether the number 3 (as a set) equals the collection of triangles in R^3 (as a set). Of course, the two aren't equal, but it seems weird to even ask this question.
Maybe it should be just as incongruous to say that some vacuum state equals it's decomposition into virtual particles. The two things are just differently-typed. You need some computation to convert between them.
Not to muddy the virtual waters here but are the "virtual ephemeral particles" of the vacuum qualitatively different from the "virtual particles" of "electrons and holes" of say semi-conductor physics which are more like mathematical, statistically aggregated entities? Or is the underlying math essentially the same?
It seems the implication is that there is a difference between abstractions and objective reality. But you are not in bad company. Max Tegmark, a physicist at MIT, believes that the fundamental substrate is math, which is just another way of saying that reality is made of mind.
I think that’s getting the cart and the horse back to front. If the fundamental substrate is math then to me that means reality is made of information.
I believe mind is a particular form of process on information, but that doesn’t mean all processes on information are minds. This IMHO is the fundamental error at the heart of panpsychism.
I believe mind is a particular form of process on information, but that doesn’t mean all processes on information are minds. This IMHO is the fundamental error at the heart of panpsychism.
Upvoted for gratuitous Greg Egan name drop
You seemingly make a strong, baseless, and unscientific ontological claim, saying that we have one set of mathematical formalisms in our theoretical model that are "really real" and others that are not "really real". Surely the word "virtual" can no more be used to support this claim than the word "imaginary" can be used to distinguish the reality of real and complex numbers.
I guess you'd be surprised then