New Nanodevice Creates a Near Perfect Electron Stream 98
SchrodingerZ writes "Scientists from the National Physics Laboratory of the United Kingdom have teamed up with the University of Cambridge to create a new electron pump that creates a single electron stream. "The device drives electrical current by manipulating individual electrons, one-by-one at very high speed." The pump takes single electrons, and pushes it over a barrier with an indent for the electron to fall into, and is then sent to the opposite side of the barrier with astounding precision. "By employing this technique, the team were able to pump almost a billion electrons per second, 300 times faster than the previous record for an accurate electron pump set at the National Institute of Standards and Technology (NIST) in the USA in 1996." Although the current was very small (150 picoamperes), this event could cause a shift from the ampere measure of current to a smaller, more precise unit of measurement for electrical current."
NPL web site offline (Score:2)
OMG, Maxwell's Demon! (Score:1)
Free energy, a new golden age ... If they can manipulate individual electrons then for sure they can manipulate individual molecules. This is even greater than sliced bread.
http://en.wikipedia.org/wiki/Maxwell's_demon [wikipedia.org]
#t33 h33 lol#
Re:OMG, Maxwell's Demon! (Score:4, Informative)
The computation/observation needed for the demon to do his thing exceeds the energy made available by doing so.
The last sentence (Score:2, Funny)
The last sentence was literally one of the stupidest things I've ever read here.
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You mean using picoamps instead of amps wouldn't be a huge revolution?
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The electron-per-second
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Also known as the "Coulomb".
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You've got it backwards. Coloumb is defined as c = a*s, while Ampere is defined as the constant current that will produce an attractive force of 2 × 10^–7 newton per metre of length between two straight, parallel conductors of infinite length and negligible circular cross section placed one metre apart in a vacuum.
Coloumb, as a unit, is derived fra Ampere. Furthermore, Coloumb is a measure of charge, not electrons, in the same way that Ampere is a measure of current, not electrions/s. If you know
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The last sentence was literally one of the stupidest things I've ever read here.
I agree.
1) Precise is precise. It either is or it isn't. Saying "more precise" is like saying "more pregnant".
2) "Amps" is dependent on voltage. If they replace anything it would be the Coulomb, not the Ampere.
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2) "Amps" is dependent on voltage.
Umm... are you sure about that?
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Sorry but no.
Ampers measures electric current flow.
Volts mesaures voltage potencial.
In some cases there is a relationship (by the means of an ideal source and an ideal resistor), but "Amps is dependent on voltage only in a specific case".
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Amperes measures electric current flow. Volts mesaures voltage potencial.
FTFY
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1) Precise is precise. It either is or it isn't. Saying "more precise" is like saying "more pregnant".
Do you work in the real world? There are varying levels of precision used in different contexts. Saying you're increasing the precision is entirely valid.
For example, a financial system that calculates using 2 digits of precision to the right of the decimal. It can be made "more precise" by using calculations that include 4 digits of precision to the right of the decimal.
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Precision is a measurable quantity. If something is "precise," it meets some arbitrary threshold of precision. That doesn't mean it can't be more precise.
Put another way, determine the precision of a measurement that is "precise." Now double the precision. Is the measurement "more precise?" Yes it is.
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No, it wasn't! It's about time we got rid of those communist nanny state pot smoking smelly hippie abortionist islam-lover lesbian ways of measuring currents and got ourselves a true American Patriot unit of measurement!
I suggest using the Patriot = 373.245 microamperes, and its subdivisions, the Liberty = 1/17 Patriots and the Apple Pie = 163/467 Liberties.
There, that should make our calculations a lot easier and our electrons a lot more macho than those wimpy Euro-electrons.
Errr (Score:4, Insightful)
"The pump takes single electrons, and pushes it over a barrier with an indent for the electron to fall into, and is then sent to the opposite side of the barrier with astounding precision. "
What is pushed over the barrier? What is sent to the opposite side of the barrier?
Sentences like this need rewriting, at the very least until they actually make some semantic sense.
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The pump pushes it (you know, "it") over a barrier. Then the pump is sent to the opposite side of the barrier. What does it mean? I don't know. My physics knowledge appears to be insufficient.
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As the great scientists of Faith No More explained in their seminal paper Epic, It's it.
Moray Valve Gone Missing (Score:1)
Too bad no one seems to be able to use this technology to make a Moray Valve (link [world-mysteries.com]).
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Yes. The hope is that once perfected, it can be re-tuned to admit electric eels and so, give us free energy.
Practical applications/implications of this? (Score:3)
Re:Practical applications/implications of this? (Score:5, Funny)
Not a guru, but the page reads the following:
"Sorry, an error occurred while processing your request"
It is usefull for warning people that this article appeared at /.
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Really obvious one, very accurate lab current standard (hook a electron pump up to a clock derived from a rubidium gas cell standard).
We can redefine the ampere with a digital definiti (Score:1)
With this, we can replace the present analog definition of the ampere, with a digital definition. One ampere is 1 coulomb of charge flowing per second. If we know how many electrons flow by per second, we can multiply by the charge of the electron to get the current in amperes.
Re:Practical applications/implications of this? (Score:5, Funny)
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Those are some danceable cables!
Do the same to protons. (Score:5, Funny)
Who you gonna call? SCIENCE!
Re:Do the same to protons. (Score:4, Funny)
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Chuck Norris streams are streams of pure meaningless bullshit.
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Proton streams?
They have a couple of those at the LHC. They even cross the streams. Twice.
Perfect (Score:1)
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It would consist of no particles or waves. A dark matter smoke ring would do the trick.
Unit of measurement (Score:2)
could cause a shift from the ampere measure of current to a smaller, more precise unit of measurement for electrical current
This made no sense to me, and it turns out that what the article says is that one might want to formulate a new definition of the ampere. What do the editors do, really?
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It made perfect sense to me, though it was still stupid. What I understood from that line was that they wanted to come up with a new unit to actually replace the ampere, at least for small-scale currents, perhaps sort of like the Angstrom is used instead of nanometers in some fields. Of course, this is entirely different from redefining the ampere, which from the way you write it I take to mean they want a new way to reproduce it, much like they changed the definition of the meter many years ago from "the
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Anyway, coming up with a new unit seems stupid to me. The whole reason SI units use prefixes like mega, giga, milli, micro, nano, pico, femto, etc. is so that you don't need new units for different scales, you just use the appropriate prefix. If this thing is in the picoamps, what's the problem? Aren't picoamps good enough?
You're right, that would be stupid—and, despite what the summary tries to tell us, that's not actually what the article's suggesting.
The ampere is currently (no pun intended) defined as the amount of current that must flow in two parallel wires a specific distance apart, in order to get a certain amount of (magnetic) force between them. (The Coulomb is then defined as the amount of charge that flows past a point in one second when the current is one Ampere.) That definition is good enough for most pur
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Yep, sounds exactly like when they redefined the meter to some number of wavelengths of some light emission.
Anyway, it sure would be nice if Slashdot had some real editors that didn't blindly accept such horribly-written article summaries.
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That is an old definition. Current one is distance light travels in 1/299792458 of a second in a vacuum.
Which has the convenient benefit of us no longer having to change the speed of light whenever we get a more precise measurement of said speed.
1A = 6.241x10^18 electrons/second (Score:5, Informative)
A billion electrons per-second = 1x10^9 which is a lot less than 1A.
A billion electrons per-second = 10^9/6.241x10^18 = 0.160nA = 160pA = 160x10^(-12) A (160 pico-amperes so pretty much the number in the article).
So while this might be a whole wack load electrons for this type of device it really is not much.
Also it might make you respect your hose wiring a little more.
Your 200A house service is (200*1A) = 1.2482x10^21 electrons per second.
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Your house service is AC at a nice integer frequency, so you end up with 0 electrons per second.
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Keep in mind that AC current just jiggles the same electrons in place, back and forth in a sine wave of velocity. The net number of electrons transferred past a point over time is approximately zero, modulo net jitter.
Nice. Closer to absolute measurements. (Score:5, Informative)
The idea here is to define the ampere as N electrons per second. This may make that possible. The number is around 6.241 Ã-- 10^18 electrons per second. Direct counts of electrons allow a precise, repeatable way to define an amp.
The goal is to define the fundamental units from measurable properties of the universe, so that reproduceable standards can be constructed. That's been achieved for time and length, but not mass. You can buy an atomic clock that gets its time measurement from the definition of the second. (HP used to make those, but that business was sold off from Agilent in 2006.) There's a method with a Kr-86 light source and interferometers to count out a meter in wavelengths of light. But there's no corresponding standard for mass. Mass is tied to a physical 1Kg weight stored in France, and everything has to be traced back to that, with each successive derived standard kilogram a little less accurate.
A kilogram ought to be defined as N atoms of something, but atom counting isn't quite good enough yet. There's a plan to define mass through the Planck constant, which means tying the standard of mass to the standard of current.
Three fundamental units are sufficient to lock down all the other units, and this is a step towards doing that.
Re:Nice. Closer to absolute measurements. (Score:5, Interesting)
A kilogram ought to be defined as N atoms of something, but atom counting isn't quite good enough yet. There's a plan to define mass through the Planck constant, which means tying the standard of mass to the standard of current.
This has been done, with a specific sized sphere (in atoms) of silicon [theage.com.au]
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Yeah but who really expects a silicon sphere to stay perfectly stable over time? Abrasion, moisture, surface contamination etc will all affect the phsyical artifact.
By counting electrons, we have a discrete, repeatable and *reproducable* measure.
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If you had read the article, you would know that this is going to be a "discrete, repeatable and reproducable" measure. I mean hell they are making two of them to start with, the only reason I imagine they aren't making more to start off with is cost.
The end product will be the exact way to construct a 1kg sphere of silicon. So new ones can be made to calibrate things etc.
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They didn't. That article claims that they planned to do it, but they couldn't achieve the necessary precision. (For an entire kilogram of mass, it is astonishing how far they got.)
Turns out that defining the Plank constant is much easier than the Avogadro constant. Anyway, CIPM decided to define both, and left the atomic mass unit floating.
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Amperes work just fine, thanks.
They work fine but they're defined in terms of the kg (force between two conductors) which is itself defined in terms of a standard kg.
If you can define the ampere in terms of number of electrons passing a point in a second (and actually count them) then you no longer need that standard kg.
I can calibrate my laboratory instruments using just the properties of the universe and some dimensionless constants.
Tim.
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Yes. and that (16) is the problem.
The amp could be *DEFINED* as 6.24150965Ã--10^18 electrons flowing past a point in one second. At the moment it is measured to be that number of electrons.
Tim.
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The problem isn't so much the (in)durability and bulk of the reference kilograms. It's more that our measurements of the kilograms' mass aren't precise enough (eg. sampling error greater than an electron's mass).
And more importantly, the transience of the mass in the kilogram. It does have a decay half life, though long, and is subject to electrostatic and photoelectric fluctuations in its electron population, and even migration of whole atoms in/out of the sample. And then there are relativistic difference
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Electrons with different quantum states aren't identical. They differ in their quantum states. If the quantum states differ in energy, the difference is hardly negligible:they have different masses.
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Picograms per bonghit?
Energy of Spin? (Score:2)
How much energy difference is there between the two electron spin states?
Could a device like this electron streamer have added a nanodevice that sets the electron's spin before it's emitted? What's the practical minimum feasible energy consumption of setting each electron's spin? And thus the energy efficiency of such a spin setter.
Better displays? (Score:1)
We can make better displays with this right - now one electron wide pixels!
I've got a good name (Score:3)
They should name the unit something related to electricity which takes parts of the picoamperes name so it sounds sort of like it. I've got it! Pikachus!
Potential for LEDs (Score:2)
being able to direct where electrons go could be a huge improvement in efficiency for LEDs. Being able to funnel the electrons directly to the quantum wells built into the p-n junction could result in an output increase of great significance.