Discovery about behavior of building block of nature could lead to computer revolution

Jul 30, 2009

(PhysOrg.com) -- A team of physicists from the Universities of Cambridge and Birmingham have shown that electrons in narrow wires can divide into two new particles called spinons and a holons.

The electron is a fundamental building block of nature and is indivisible in isolation, yet a new experiment has shown that , if crowded into narrow wires, are seen to split apart.

The electron is responsible for carrying in wires and for making magnets. These two properties of magnetism and electric charge are carried by electrons which seem to have no size or shape and are impossible to break apart.

However, what is true about the properties of a single electron does not seem to be the case when electrons are brought together. Instead the like-charged electrons repel each other and need to modify the way they move to avoid getting too close to each other. In ordinary metals this does not usually make much difference to their behaviour. However, if the electrons are put in a very narrow wire the effects are exacerbated as they find it much harder to move past each other.

In 1981, physicist Duncan Haldane conjectured theoretically that under these circumstances and at the lowest temperatures the electrons would always modify the way they behaved so that their magnetism and their charge would separate into two new types of particle called spinons and holons.

The challenge was to confine electrons tightly in a 'quantum wire' and bring this wire close enough to an ordinary so that the electrons in that metal could 'jump' by into the wire. By observing how the rate of jumping varies with an applied field the experiment reveals how the electron, on entering the quantum wire, has to fall apart into spinons and holons. The conditions to make this work comprised a comb of wires above a flat metal cloud of electrons. The Cambridge physicists, Yodchay Jompol and Chris Ford, clearly saw the distinct signatures of the two new as the Birmingham theorists, Tim Silk and Andy Schofield, had predicted.

Dr Chris Ford from the University of Cambridge's Cavendish Laboratory says, 'We had to develop the technology to pass a current between a wire and a sheet only 30 atomic widths apart.

'The measurements have to be made at extremely low temperatures, about a tenth of a degree above absolute zero.

'Quantum wires are widely used to connect up quantum "dots", which may in the future form the basis of a new type of computer, called a quantum computer. Thus understanding their properties may be important for such quantum technologies, as well as helping to develop more complete theories of superconductivity and conduction in solids in general. This could lead to a new computer revolution.'

Professor Andy Schofield from the University of Birmingham's School of Physics and Astronomy says, 'The experiment to test this is based on an idea I had together with three colleagues almost 10 years ago. At that time the technology required to implement the experiment was still a long way off.

'What is remarkable about this new experiment is not just the clarity of the observation of the spinon and holon, which confirms some earlier studies, but that the spinon and holon are seen well beyond the region that Duncan Haldane originally conjectured.

'Our ability to control the behaviour of a single electron is responsible for the semiconductor revolution which has led to cheaper computers, iPods and more. Whether we will be able to control these new particles as successfully as we have the single electron remains to be seen. What it does reveal is that bringing electrons together can lead to new properties and even new particles.'

More information: The paper is published in Science at dx.doi.org/10.1126/science.1171769

Source: University of Cambridge (news : web)

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User comments : 4

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frajo
1 / 5 (1) Jul 30, 2009
"One difficulty of the spin-charge separation is that, spinon and chargon are not gauge invariant quantities, i.e. unphysical objects".
http://en.wikiped...i/Spinon
Alizee
Jul 30, 2009
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Alizee
Jul 30, 2009
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Alizee
Jul 30, 2009
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gmurphy
Jul 30, 2009
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Alizee
Jul 30, 2009
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Yes
not rated yet Jul 31, 2009
My simplistic view is that in normal current through thick wires the resulting current is going in one direction while the electrons move back and forth.
In this ultra thin wire all the electrons move in one direction so when we apply Debroglie wavelength to a line of moving electrons we can imagine the electrons acquire coherence forming 'yes' a particle laser and the electrons go in and outof existence along the moving path. This leaves us with linebits of electrons and linebits of nothing. The negative charged linebits of existing electrons will repulse the following negative charged linebits while there is nothing in between resulting in what they see.
There is thousands of volts between the linebits, so the forces between the bits is enormous. It may break the wire in my imagination
Alizee
Jul 31, 2009
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RayCherry
5 / 5 (1) Aug 05, 2009
Yes, replace 'nothing' with 'neutrally charged spinbits' and I think you have it almost right.

Alizee, discussing AWT on PhysOrg is interesting and informative for all concerned, but post AWT explanations to articles that obviously try their best to ignore AWT is just being contentious.

In all science generally, and physics especially, there exist different philosophies to explain 'the unknown' and some of those are better accepted by the peers and their sponsors than others. Attempting to keep a less-sponsored philosophy alive by applying it to everyone else's work is almost a religious crusade. Please don't reduce AWT to that.

Personally I think there is space for more than one explanation of any area of science that is currently 'unknown', and that it is up to the different proponents to invite sponsorship for experimentation and validation. One group applying their explanations to the results of the experiments of another group is not only impolitic, it causes rifts between the groups that are better avoided.

In today's science, many ideas that were previously dismissed are being re-examined, as if the original proponents had an intuitive vision of the science that which was being tested and examined by others.

Inform and assist the better sponsored science teams, even humbly forego the limelight, if it means that recognition of the work of different branches of science/philosophy eventually become united.

Remember that the roots of sceince were in the study of nature, natural law and philosophy, and also that dogmatic teaching is the absolute nemesis of modern science, (even if so much appears to be intrinsic in the modern highly-sponsored field).

Now that most are considering the Mass, Charge, Magnetic Field and the Spin of partcles - even in 'mundane electric circuits' - perhaps we are closer to seeing the validations of older theories ... especially as we see the effects of 'groups' rather than 'individual' particles.

;-) Good luck everybody
nonoice
not rated yet Aug 06, 2009
RayCherry Well said....

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