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What Is a Particle? (2020)

quantamagazine.org

71–80 of 196 posts

Re: What Is a Particle? (2020)

#71
post #24

That's why calling Higgs Boson the God particle is not quite right. It's the Higgs field that gives mass to the other particles, not the Boson. A Higgs Boson is just an excitation of the Higgs field; it doesn't give mass to other particles. In fact it's the Higgs field modifying the other fields causing their excitations (particles) to slow down when passing each other, thus gaining masses.

Actually it doesn't seem to be that simple. Higgs Boson seems to contribute mainly to masses of leptons (mostly electrons) and bosons W and Z. And that influence goes to zero at high energies of the measures system making W and Z weightless and merging electrostatic and weak interactions into a singular electroweak interaction.

Quarks get most of their mass from QCD with very minor contribution from Higgs Boson. And nobody has any idea where the mass of neutrinos comes from.

It also has no influence on photons and gluons.

Higgs seems to be very peculiar and not very universal mechanism. I wonder if one of the potential future approaches won't do away with Highs Boson (together with virtual particles) as artifacts of specific math approach and interpretation without any physical manifestation.

Higgs was detected, sure, but it was detected through an interpretation of the data through the best available mathematical model which some postulate might contain some purely mathematical constructions along the way to the ultimate real world result.

Re: What Is a Particle? (2020)

#72
post #4

I'm honestly surprised that more people don't go mad in certain fields. If I ponder for 10 minutes the inexplicability of the universe's existence, or the vastness of space, my mind starts to breaks down.

It's just a puzzle and should be taken as such.

Re: What Is a Particle? (2020)

#73
post #60

Issues: (1) With Itself: Consider Young's double slit experiment: So, have plane with two slits and some distance away a parallel plane with detectors. (A) Several times, shoot a photon at the slit. Observe that the detection locations form parallel lines, i.e., fringes . (B) Cover one slit, repeat, and observe that the detection locations from a smooth hill without fringes. So, from (A) we conclude that the somethin…

You can't detect without affecting.

My idea for resolving this is that electron is never a point-like particle. It's always a cloud, just larger or smaller. When it's detected it gets reshaped to be narrower. Mass, energy, momentum and such are a quantities ascribed to the whole cloud and exchanged only on the moment of interaction.

Think about diffraction. Photon or electron that passes through a small hole had it's moment messed up proportionally. It becomes large again.

Interesting question is where's the gravity in all of this. There are various ideas how to match quantum uncertainty to shape of space-time.

Re: What Is a Particle? (2020)

#74
post #16
post #7

I have another definition, or at least this is how I think of it. I’m not sure many people would buy into it. In the standard model, the fermions are particles, like the electrons, quarks, neutrinos. Electroweak, strong force, gravity are fields. This means the photon is not a particle, but just a field excitation. I know people can think of fermions as fields, I just think of them as particles.

Aren't you describing quantum field theory (QFT)? Anyway, what exactly is a field besides a mathematical object? What is it made of?

I did study quantum field theory and I have a hard time viewing a fermion as a continuous field, whereas a gauge field I do view as a continuous field. I view a fermion as a true point particle, kind of like it is in a lattice. The fermion still has a wave function of course. It is very different from the wave function of a gauge field. The wave function of an electric field is a wave function over field configurations. The fermion wave function is a wave function of fermion spins. I don't think this is an unreasonable view, but I am not trying to force it on anyone else.

Re: What Is a Particle? (2020)

#75
post #4

I'm honestly surprised that more people don't go mad in certain fields. If I ponder for 10 minutes the inexplicability of the universe's existence, or the vastness of space, my mind starts to breaks down.

It's just a puzzle and should be taken as such.

The universe is a puzzle?

Re: What Is a Particle? (2020)

#76
post #60

Issues: (1) With Itself: Consider Young's double slit experiment: So, have plane with two slits and some distance away a parallel plane with detectors. (A) Several times, shoot a photon at the slit. Observe that the detection locations form parallel lines, i.e., fringes . (B) Cover one slit, repeat, and observe that the detection locations from a smooth hill without fringes. So, from (A) we conclude that the somethin…

You can't detect without affecting. My idea for resolving this is that electron is never a point-like particle. It's always a cloud, just larger or smaller. When it's detected it gets reshaped to be narrower. Mass, energy, momentum and such are a quantities ascribed to the whole cloud and exchanged only on the moment of interaction. Think about diffraction. Photon or electron that passes through a small hole had it's…

> You can't detect without affecting.

"These detectors are distant enough that what they do cannot affect the electron, i.e., the electron does not know about the detectors."

We detect gravitational waves without "affecting".

The electron mass and charge send out signals. Have the detectors sufficiently far away that they can't affect the particle yet. Get the detection and then know where the particle was and its mass and charge then. Have the particle reflected by some mirrors and then know the current path of the particle and its mass and charge, all without affecting the particle.

Re: What Is a Particle? (2020)

#78

I'm reading "The Big Picture" (Sean Carroll) right now. I'd love to have a real physicist explain this, but: When we think of what a particle IS, we often think as though it were dirt, or a billiard ball, or something. As though there were some other substance of which it's made. At least I do. But the definition is as low as you can go. It's hard to wrap your head around that. Unless you're trained to do so, I guess…

It's a useful fiction, but the map is not the territory. This sounds blithe but ... it is as close as you will get to the truth.

I only got the bachelors' version of physics, though I did take some grad classes, so here is what I will tell you:

The human mind learns from experience and it thinks of things in terms of the past experiences it has had. We are big assemblages which exist in a narrow range of temperatures (think in terms of Kelvin). Our experience is classical, in the Newtonian sense: we move at not a particularly notable fraction of c, we are too warm to note the strangenesses which happen below, say, twenty or four or a thousandth of a Kelvin (superfluids and BECs are out), we are too cold to have a great internal experience of plasma, leaving us to be creatures of solid and liquid, with a sort of inferred understanding of gas. We are too large to feel the quantum realm, in the sense that the uncertainty principle is not obvious to us from what we have felt.

So, we must make do with abstractions, with fictions, with approximations. Conscious that we are the epitome of the six blind men trying to understand the elephant through touch alone, we try to break our understanding, to search for flaws in our inferences. Yet this does not grant us true experience when we run across, say, the electron. We try to think of it like a billiard ball, but we can say that a billiard ball is this wide, yet we are fairly sure at this time that the electron has no radius, no diameter, that it might as well be a geometric point. Every time we try to measure, we can only establish a smaller and smaller upper bound for the confounded thing's radius. That's not like our lives at all!

The reality of this electron is that if we get it going fast enough, it stops getting much faster no matter how hard we smack it. That's not like our reality. If we try to pin down where it is, the more we do it, the harder it is to figure out how fast and in what direction it moves. And as we work to ascertain the velocity (and therefore momentum), we lose sense of this bit of weirdness' position.

You eventually have to develop an understanding based not on experience at all.

Perhaps this was unique to me, but the first time I understood integration in calculus, I had a brief moment of dizziness as I apprehended this new thing. You know how you are working a math problem and you have a good idea of what the answer is already, a sense of what the magnitude and direction might be? I had ground my way through vector and tensor calculus, and had been working a problem in gravitation and relativity class when I sensed what the resulting tensor would look like, the shape of it, in the sense that I would know if my figures were way off. I nearly fell off the chair, my head spun so.

If you care to, you can do this for a particle.

Re: What Is a Particle? (2020)

#79
post #9

Earlier quoted context omitted.

> we often think as though it were dirt, or a billiard ball, or something The problem lies that it is hard to imagine something that does have zero dimensions. You can get the example of ant walking into 2D and it is unaware of third dimension to explain we are have something similar for space-time 4D (although not the same picture exactly as time is different from spatial dimensions). But we don't have an idea how t…

> The problem lies that it is hard to imagine something that does have zero dimensions. Do you really think so? It’s not hard to picture the real number line, with the point zero (or any other single point) distinguished. Sure — if you draw it in the standard schematic way you have to give it some area, but it still seems quite intuitive that it’s ‘zero-dimensional’. Especially if you play around with converging sequ…

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Re: What Is a Particle? (2020)

#80

I'm reading "The Big Picture" (Sean Carroll) right now. I'd love to have a real physicist explain this, but: When we think of what a particle IS, we often think as though it were dirt, or a billiard ball, or something. As though there were some other substance of which it's made. At least I do. But the definition is as low as you can go. It's hard to wrap your head around that. Unless you're trained to do so, I guess…

I've only got a physics minor, so hardly an expert, but I felt like quantum mechanics got a lot easier once I started thinking of a particle as merely a situation which has some probability of causing a state change in a detector of some kind.
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