New Fundamental Particles?

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djolds1
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New Fundamental Particles?

Post by djolds1 »

Spinons and holons.

The latest development in particle physics reveals the "indivisible" electron might not be so indivisible in all situations. Scientists at Cambridge University have discovered that electrons in quantum-scale wires can break into two smaller particles, called spinons and holons.

The breaking-apart effect only happens when a lot of electrons are competing for not a lot of space. Since the electrons repel each other, if they are put into a very narrow wire, they find it harder and harder to move past each other. The electrons apparently respond by breaking their magnetism and charge into two separated particles, the spinons and holons.

The experiment that this team used to test their breaking-up-electron hypothesis is also pretty interesting. The team had to get electrons into a very thin wire, take the whole thing down to near-absolute-zero temperatures, and then observe how electrons bounced between that wire and a close-by metal.

When the metal and the wire are near each other, the electrons do their "quantum tunneling" thing, and the scientists take measurements under a variety of magnetic fields to see what is happening when the electrons jump. These measurements eventually indicated that the jumping electrons had to be falling apart into two new particles.

The discovery, detailed in Science magazine, has some pretty strange implications for particle physics, but it also might prove important in quantum computing. Quantum wires are used to connect components in a quantum computer, and these computers might have to account for the effect of these distressed electrons breaking into smaller particles. If nothing else, high school science teachers might have to put a new spin on the "indivisible electron" story.
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djolds1
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Re: New Fundamental Particles?

Post by djolds1 »

Never mind?

Goddamn sensationalist condensed-matter guys and their lying headlines. The electron has not been "split" into anything. This result shows that the bulk behavior of a group of electrons can be more easily described by fictional particles called a "spinon" and "holon".

These particles do not exist. They are just a more convenient description for the mass behavior of electrons in certain situations. This is analogous to how people talk about "sound waves" and "phonons" for vibrations: there is no such particle as a phonon, and no such discrete thing as a "sound wave", just air molecules vibrating back and forth. But the behavior of vibrating atoms and molecules is easier to talk and reason about when you introduce a thing called a phonon, and then describe wave phenomena in terms of that.

As an aside: electroweak theory (QED) makes some very definite predictions about the number and character of fundamental particles. If the electron really could split, we (high-energy physicists) would have seen it before now in measurements of things like the Z boson resonance.

I hate sensationalist bullshit like this headline.


-----

I think you mean "an electron is about as real as it gets". The whole point is that the many-body spectrum of a bunch of electrons is massively complicated, and beyond a handful it no longer makes sense to talk about each one's individual motion when there are far less energetic but well-defined states available.

At the end of the day, we're all looking at the low energy spectrum of some system, and trying to describe it in simple terms. A small bunch of electrons makes sense for what we call "the vacuum". People usually call excitations of this "vacuum" fundamental, and I would go with it if we knew that this vacuum was somehow preferred, beyond historical accident. Until we do, and even if we did, it might still make sense to simply treat it as we do any other material.

Finally, I'd like to weigh in against calling creating spinons and holons "splitting" the electron. Nothing has been split. We moved a certain amount of stuff (energy, momentum, etc.) between two systems, and found that it corresponds to different combinations of excitations. Dressing it up doesn't help anyone.
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MSimon
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Post by MSimon »

I think in the quantum Hall effect electrons have 1/2 charge. Or maybe it was some other situation. Definitely 1/2 charge though.

At the time I looked at it there was no explanation.
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gblaze42
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Post by gblaze42 »

Who ever that was, is correct. I've seen this described using the wave function of an electron as well.



Woe to the victors?

djolds1
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Post by djolds1 »

gblaze42 wrote:Woe to the victors?
"Woe to the conquered"
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gblaze42
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Post by gblaze42 »

djolds1 wrote:
gblaze42 wrote:Woe to the victors?
"Woe to the conquered"
I was just posing a question., in regards to your signature.

djolds1
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Post by djolds1 »

gblaze42 wrote:
djolds1 wrote:
gblaze42 wrote:Woe to the victors?
"Woe to the conquered"
I was just posing a question., in regards to your signature.
No offense taken. "Woe to the Unconquered" would be "Vae Invictis."
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EricF
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Post by EricF »

With regard to fundamental particles, what ever happened with the Higgs Boson hysteria we had last year?

Speaking of which, doesn't it seem like kind of a chicken and egg scenario with regards to the Higgs particle. The premise is, they are trying to smash protons together to find in the debris a particle which causes other particles to come into existence. So what obliged that particle to materialize from the ether, so it could go on creating other particles? How do they reconcile that? With String Theory?

MSimon
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Post by MSimon »

EricF wrote:With regard to fundamental particles, what ever happened with the Higgs Boson hysteria we had last year?

Speaking of which, doesn't it seem like kind of a chicken and egg scenario with regards to the Higgs particle. The premise is, they are trying to smash protons together to find in the debris a particle which causes other particles to come into existence. So what obliged that particle to materialize from the ether, so it could go on creating other particles? How do they reconcile that? With String Theory?
Don't worry. Eventually they will get to rope theory.
Engineering is the art of making what you want from what you can get at a profit.

djolds1
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Post by djolds1 »

MSimon wrote:Don't worry. Eventually they will get to rope theory.
???
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MSimon
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Post by MSimon »

djolds1 wrote:
MSimon wrote:Don't worry. Eventually they will get to rope theory.
???
It is like string theory only it can carry heavier loads.
Engineering is the art of making what you want from what you can get at a profit.

djolds1
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Joined: Fri Jul 13, 2007 8:03 am

Post by djolds1 »

MSimon wrote:
djolds1 wrote:
MSimon wrote:Don't worry. Eventually they will get to rope theory.
???
It is like string theory only it can carry heavier loads.
Ah. Neo-epicycles. Gotcha.
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KitemanSA
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Post by KitemanSA »

djolds1 wrote:
MSimon wrote:
djolds1 wrote:???
It is like string theory only it can carry heavier loads.
Ah. Neo-epicycles. Gotcha.
Besides, if you give them enough rope...

tomclarke
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Re: New Fundamental Particles?

Post by tomclarke »

djolds1 wrote: These particles do not exist. They are just a more convenient description for the mass behavior of electrons in certain situations. This is analogous to how people talk about "sound waves" and "phonons" for vibrations: there is no such particle as a phonon, and no such discrete thing as a "sound wave", just air molecules vibrating back and forth. But the behavior of vibrating atoms and molecules is easier to talk and reason about when you introduce a thing called a phonon, and then describe wave phenomena in terms of that.

As an aside: electroweak theory (QED) makes some very definite predictions about the number and character of fundamental particles. If the electron really could split, we (high-energy physicists) would have seen it before now in measurements of things like the Z boson resonance.

I hate sensationalist bullshit like this headline.
I agree with the hate - a thoroughly (and deliberately) misleading article! Just a quibble. There is nothing wrong with the description as spinons and holons - it is a useful approximation to behaviour of "electrons" under certain 1D boundary conditions.

Equally "electrons" is a useful approximation to the behaviour of the wave function under (much more typical) physically localised conditions.

Both electrons and spinons, holons are descriptive metaphors - one has a wider domain of application than the other.

It is true that we usually identify electrons as fundamental particles and this is valid whatever the conditions (at energy levels where electrons exist). And in this respect one electron represents a given number of invariants, degrees of freedom, etc and is fundamental.

So although electrons (as a particle) and spinons,holons are descriptive metaphors of similar status, we normally think of electrons as fundamental particles and this has much more validity than spinons/holons.

Best wishes, Tom

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