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Old 06-June-2008, 06:45 PM
suyuti suyuti is offline
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Default New 'Quasiparticles' Discovered; May Pave Way Toward New Quantum Computer

Cool. Took its time though.
See:
http://www.sciencedaily.com/releases...0602103355.htm
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Old 07-June-2008, 11:24 AM
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'Quasiparticles'?!

My, my, modern particle physics is so full of subtleties and nuances it's starting to sound like English lit!
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Old 07-June-2008, 03:49 PM
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Strictly speaking, this is not actually particles physics. It is about many particles that interact with each other.

The concept of quasiparticles was developed by Landau to explain the properties of electrons in metals.
As a first approximation, these electrons can be described as gas of particles that do not interact with each other. But to take into account that they are inside a crystal lattice, which affects how they react to external fields, their mass has to be corrected. The result is that the particles used to describe the electric properties of metals are no longer simple electrons, but electron-like particles.

This is similar to the small oscillations in analytical mechanics: close to equilibrium a system can be described in term of a set of oscillators, which are not necessarily parts (or particles) of the system literally oscillating.

And, as a matter of fact, this is directly used in solid state physics. For example, the properties of the crytal lattice close to equilibrium are described in terms of quasiparticles called "phonons", which correspond to the oscillations of atoms. The long-range properties of the electrons in a metal are described in terms of "plasmons", which correspond to long-range oscillations of the charge density of the electrons.

There are many more example in condensed matter physics.

In the case of the OP, we have a gas of electrons confined to a plane and in a strong magnetic field. In this case, the quasiparticles used to describe the system correspond a a number of electrons "bound" to a number magnetic flux quanta. So, if we look at single flux quantum, we can have a fractional electron charge.
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Old 07-June-2008, 04:47 PM
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So, any opinions on what should the headline have been? "Discovered" doesn't sound right. "Invented" might not be temporally correct, for the quasiparticles were imagined before now. Could it be that the quasiparticles have been "confirmed to be useful"? Hmm...
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Old 07-June-2008, 10:41 PM
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So, how long before I can burn virtual rubber with this on my pc?
I do believe that someday quantum computers will be useful for scientific use at least, and maybe even someday for a PC, but it hasn't quite been the 'magic' some of the more bubblier and enthused make it out to be.
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Old 11-June-2008, 10:39 AM
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I found the news in Nature about this:
Quote:
On page 829 of this issue, Dolev et al. report the detection of vortices in a fluid of electrons confined to two dimensions within a semiconductor structure that carry just 1/4 of the electron's charge. These 'quasiparticles' are an exciting find: according to theoretical predictions, their collective behaviour should be described by an unusual type of particle statistics known as non-abelian statistics. Above all, that could make them useful in an exotic, but highly promising, brand of quantum computer — the topological quantum computer (see News Feature on page 803).
So, the interesting part is not the fact that these are quasi-particles with fractional electronic charge, but that the expected statistics of their collective behaviour is exotic.
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Old 11-June-2008, 03:13 PM
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Quote:
So, the interesting part is not the fact that these are quasi-particles with fractional electronic charge, but that the expected statistics of their collective behaviour is exotic.
Ah-h-h-h-h-h! Finally the subcharge structure of the Higgs field begins to shine.
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Old 30-June-2008, 09:05 PM
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Now I remember hearing about "super chemistry"--where molecules could act as a discrete atom...could there be a spin off here too?
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