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New Nanodevice Creates a Near Perfect Electron Stream

samzenpus posted about 2 years ago | from the don't-cross-the-streams dept.

Science 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."

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98 comments

aloco (-1, Offtopic)

Anonymous Coward | about 2 years ago | (#40624037)

cambio !!!!

english mother fucker (-1)

Anonymous Coward | about 2 years ago | (#40624329)

cambio !!!!!

DO YOU SPEAK IT?!?

Filter error: Don't use so many caps. It's like YELLING.

NPL web site offline (1)

k(wi)r(kipedia) (2648849) | about 2 years ago | (#40624039)

NPL web site appears to be offline at the time of this post. Maybe they couldn't handle the deluge of electrons headed their way. Science Daily link okay though.

Re:NPL web site offline (-1, Troll)

Anonymous Coward | about 2 years ago | (#40624247)

I fart out of my fuckyhole!

I was aiming at the first post (0)

Anonymous Coward | about 2 years ago | (#40624041)

But my electron pump isn't that precise...

WTF ?!? (-1)

Anonymous Coward | about 2 years ago | (#40624045)

#BORKED

OMG, Maxwell's Demon! (1)

Anonymous Coward | about 2 years ago | (#40624047)

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! (3, Informative)

The Master Control P (655590) | about 2 years ago | (#40624569)

Keep dreaming.

The computation/observation needed for the demon to do his thing exceeds the energy made available by doing so.

Re:OMG, Maxwell's Demon! (-1)

Anonymous Coward | about 2 years ago | (#40625487)

The computation/observation needed for the demon to do his thing exceeds the energy made available by doing so.

Based mainly on circular reasoning.

It also assumes that the position of the molecules in an enclosed space have to be measured and doesn't behave in a deterministic way.

Re:OMG, Maxwell's Demon! - gotcha (0)

Anonymous Coward | about 2 years ago | (#40626397)

Did you wonder about the #t33 h33 lol# ?

Tee Hee LOL

When you see a post that begins with OMG, it should alert you to the fact that it may not be entirely serious.

Anyway, as the other AC who replied to you pointed out, there is no rigorous proof that Maxwell's Demon is impossible. If there were a solid proof of that then we probably wouldn't remember Maxwell's Demon. It's one of those things that shows us the limits of our understanding.

Re:OMG, Maxwell's Demon! (0)

Anonymous Coward | about 2 years ago | (#40626437)

The computation/observation needed for the demon to do his thing exceeds the energy made available by doing so.

Send in the logic probe!

Re:OMG, Maxwell's Demon! (0)

Anonymous Coward | about 2 years ago | (#40626781)

On the other hand, see: graphene separating water molecules and absolutely everything else in the water.

The last sentence (2, Funny)

Anonymous Coward | about 2 years ago | (#40624049)

The last sentence was literally one of the stupidest things I've ever read here.

Re:The last sentence (2)

siddesu (698447) | about 2 years ago | (#40624093)

Not to mention that the Thomson is already taken, and the Millikan would be an unfortunate choice, as people will uncontrollably multiply it by a thousand.

Re:The last sentence (2)

durrr (1316311) | about 2 years ago | (#40624489)

You mean using picoamps instead of amps wouldn't be a huge revolution?

Re:The last sentence (1)

kubernet3s (1954672) | about 2 years ago | (#40625147)

Enter....

The electron-per-second

Re:The last sentence (2)

Joce640k (829181) | about 2 years ago | (#40625727)

Also known as the "Coulomb".

Re:The last sentence (0)

Anonymous Coward | about 2 years ago | (#40626695)

Also known as the "Coulomb".

Hmm, sorry but no. A Coulomb is a finite number of electrons. An Amp is 1 Coulomb/second.. thus is the measure of the electrical flow. What the parent was suggesting, was a new Amp-like definition where you use 1 electron rather than Coulomb electrons.

Re:The last sentence (2)

ThreeKelvin (2024342) | about 2 years ago | (#40627519)

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 that your current results from a stream of electrons, instead of say, ions, protons, or positrons, then you can calculate the corresponding electrons/s.

Still, you're right that GP is wrong.

Re:The last sentence (0)

Joce640k (829181) | about 2 years ago | (#40625741)

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.

Re:The last sentence (1)

psmears (629712) | about 2 years ago | (#40626409)

2) "Amps" is dependent on voltage.

Umm... are you sure about that?

Re:The last sentence (1)

siddesu (698447) | about 2 years ago | (#40626565)

If you happen to measure either charge or time in volts, it is.

Re:The last sentence (3, Informative)

CatBandit (866637) | about 2 years ago | (#40626587)

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".

Re:The last sentence (0)

Anonymous Coward | about 2 years ago | (#40626669)

Woosh. Who measures either charge or time in volts?

Re:The last sentence (1)

teh dave (1618221) | about 2 years ago | (#40635311)

Amperes measures electric current flow. Volts mesaures voltage potencial.

FTFY

Re:The last sentence (0)

Anonymous Coward | about 2 years ago | (#40627121)

You are incredibly stupid to not understand precision. Something can be precise to X decimal places. Accuracy is the validity/tolerance of such a statement.

Re:The last sentence (0)

Anonymous Coward | about 2 years ago | (#40627153)

I think you got that backwards...

"In the fields of science, engineering, industry and statistics, the accuracy[1] of a measurement system is the degree of closeness of measurements of a quantity to that quantity's actual (true) value. The precision[1] of a measurement system, also called reproducibility or repeatability, is the degree to which repeated measurements under unchanged conditions show the same results.[2] Although the two words reproducibility and repeatability can be synonymous in colloquial use, they are deliberately contrasted in the context of the scientific method."

https://en.wikipedia.org/wiki/Accuracy_and_precision

Re:The last sentence (0)

Anonymous Coward | about 2 years ago | (#40627363)

You can increase the level of precision. However, I understand where you are coming from. If someone says precise, you think 'exact'. Unfortunately, in the scientific world, precise doesn't really mean exact- the amount of precision can be adjusted.

Re:The last sentence (0)

Anonymous Coward | about 2 years ago | (#40627485)

If I have a voltage source that changes very little, and I measure it with one voltmeter, it might say it is 1.52 volts, then 1.54 volts when I measure a second time, and 1.51 volts when I measure third time, etc. Hence it has a precision on the order of 10 mV. If I get a different voltmeter that gives measurements of 1.512 V, 1.513 V, and 1.510 V, that second voltmeter has a precision on the order of mV. Hence the second voltmeter is more precise. Precision is just a measure of how repeatable measurements are (sort of like signal to noise ratio for the measurement).

This is contrasted with accuracy, which is how far the measurement is from "actual" value. You could send a first voltmeter off to be calibrated against a NIST standard, and then afterwards, find out your voltage source was actually 1.00 V plus or minus 10 mV. The second voltmeter is still more precise, just really inaccurate.

Re:The last sentence (1)

SimplyGeek (1969734) | about 2 years ago | (#40627829)

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.

Re:The last sentence (1)

ceoyoyo (59147) | about 2 years ago | (#40628835)

1) Precise is precise. It either is or it isn't. Saying "more precise" is like saying "more pregnant".

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.

Re:The last sentence (1)

daem0n1x (748565) | about 2 years ago | (#40627823)

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 (4, Insightful)

Anonymous Coward | about 2 years ago | (#40624057)

"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.

Re:Errr (1)

Anonymous Coward | about 2 years ago | (#40625583)

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.

Re:Errr (1)

darkshadow (102598) | about 2 years ago | (#40628275)

As the great scientists of Faith No More explained in their seminal paper Epic, It's it.

back-tunneling? Tilting at atomic level? (0)

Anonymous Coward | about 2 years ago | (#40627889)

The dot can be filled with electrons and then raised in energy. By a process known as 'back-tunneling', all but one of the electrons fall out of the quantum dot back into the source lead. Ideally, just one electron remains trapped in the dot, which is ejected into the output lead by tilting the trap. .

Can any one care to explain what back-tunneling or tilting at atomic level mean?

Moray Valve Gone Missing (1)

Anonymous Coward | about 2 years ago | (#40624077)

Too bad no one seems to be able to use this technology to make a Moray Valve (link [world-mysteries.com] ).

Re:Moray Valve Gone Missing (3, Funny)

Anonymous Coward | about 2 years ago | (#40624385)

Is that a valve that selectively lets through moray eels, but blocks all other Anguilliformes?

Re:Moray Valve Gone Missing (1)

sjames (1099) | about 2 years ago | (#40629511)

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? (2)

Dyinobal (1427207) | about 2 years ago | (#40624109)

Can any science/physics gurus tell me what sort of practical applications this has?

Re:Practical applications/implications of this? (5, Funny)

marcosdumay (620877) | about 2 years ago | (#40624157)

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 /.

Re:Practical applications/implications of this? (2)

schn (1795404) | about 2 years ago | (#40624169)

Precise electron flow, let me guess, lower power electronics.

Re:Practical applications/implications of this? (1)

Anonymous Coward | about 2 years ago | (#40624177)

All sorts of useful things like death rays, CRT TVs for bacteria, and e-beam lithography. Maybe.

Re:Practical applications/implications of this? (0)

Anonymous Coward | about 2 years ago | (#40625589)

How is this post not at +5, Funny?

Re:Practical applications/implications of this? (0)

Anonymous Coward | about 2 years ago | (#40626581)

How is this post not at +5, Funny?

Because it's not that funny. Duh.

Re:Practical applications/implications of this? (2, Informative)

Anonymous Coward | about 2 years ago | (#40624181)

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 (1)

Anonymous Coward | about 2 years ago | (#40624231)

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? (4, Funny)

Krishnoid (984597) | about 2 years ago | (#40624255)

Well, an extremely-low jitter audio signal finally worthy of transfer over your Pear Anjou [pearcable.com] cables comes to mind right away.

Re:Practical applications/implications of this? (1)

tkrotchko (124118) | about 2 years ago | (#40625545)

Those are some danceable cables!

Re:Practical applications/implications of this? (0)

Anonymous Coward | about 2 years ago | (#40625877)

Well you could try to set the record for most wave-particle duality experiments per seconds. But they'll probably use it for something boring like extra low current consuming memory or cpu.

edit. just got a deja-vu on the captcha's 0.0

Re:Practical applications/implications of this? (0)

Anonymous Coward | about 2 years ago | (#40678481)

There are a few different angles on this experiment.

1) Metrology: The way the SI electrical units are defined is a bit different to how they are implemented practically. Electrical units actually enter the SI system through the ampere, rather than the volt and the ohm. Because the definition of the ampere is based on forces between current carrying wires, this involves the kilogram, a lump of metal that lives in a vault in France. To some extent this limits the accuracy with which the ampere can be 'realised', and is a bit unsatisfactory to some people who don't like the idea of using an 'artefact' (the kilogram) that can't be perfectly duplicated in different labs all over the world.
In fact, two well-established quantum effects, the quantum hall and Josephson effect, mean that voltage and resistance can already be measured accurately against effects that appear to be truly independent and universal, depending only on fundamental constants (Plank's constant and the electron charge). Most people probably don't realize that quantum units are ALREADY USED in practice to calibrate the voltmeters and standard resistors that then get sent out to secondary calibration labs and eventually are used to calibrate equipment used on the 'factory floor' (there is a chain of 'traceability').
There is, however, still a discrepancy between the formal SI units and the 'practical' quantum units. In order to fix this, you need to formally switch the definitions to place the quantum system at the core. Before you do this, you need a few things, like 1) a way of 'measuring' Planck's constant and 2) an internal consistency checks on the electrical relationships that relate the quantum ohm, the quantum volt and the quantum ampere. For the first thing you use a contraption called a 'Watt balance'. For the second, you can use an accurate electron pump to do the consistency check. This is sometimes called the 'the quantum metrological triangle'. Actually, if it turned out to be practical, you could even use the electron pump to actually calibrate things, but in practice most people use standard resistors and voltage references to transfer calibration information.
You might wonder why metrologists care about it so much, but this change to the units system is quite profound, including redefining the kilogram, so it is quite important that you have tested everything properly. Most people will never notice the difference, because numerically the change will be quite smooth, but anybody technical/scientific should really know what those new units really 'mean'.

2) 'Quantum circuitry' (this is a bit more speculative)
People have been doing quantum mechanics with photons (light) for years, and have developed some clever applications like quantum cryptography. It would be nice to do the same kind of thing with electrons in a semiconductor system for reasons of scalability and integration with existing semiconductor technology. With some tricks you can use low dimensional semiconductors systems (like the layered material the electron pump is made from) and reproduce 'quantum' effects, but this technology is not as advanced as the optical systems. This is partly because it is much harder to preserve the quantum state of an electronic system because it tends to interact strongly with all other degrees of freedom in the system, like the lattice of ions and fluctuations in the background field from the nuclear spins etc. Still, people are getting better all the time and making these systems work, albeit using expensive cryogenic techniques and fancy high frequency electronics. Single-electron sources might be seen as part of a 'toolkit' that you might use for this kind of experiment. As for applications, I almost dare not use the phrase 'quantum computing' because this idea has been hyped up so much, but there is a hope that these delicate quantum effects will be good for something eventually. Even in the absence of the deeply 'quantum' aspect, the source might make certain devices possible, like on-demand single photon sources.

The summary above is actually misleading (the bit about making the ampere 'smaller').
If you actually care, you can read the full paper on the ArXiv http://arxiv.org/abs/1201.2533

Do the same to protons. (4, Funny)

p0p0 (1841106) | about 2 years ago | (#40624225)

We focus protons the same and we can start catching some ghosts.
Who you gonna call? SCIENCE!

Re:Do the same to protons. (3, Funny)

GoodNewsJimDotCom (2244874) | about 2 years ago | (#40624527)

Those are also known as Chuck Norris streams, because you do not cross them or people might die.

Re:Do the same to protons. (1)

Doc Ruby (173196) | about 2 years ago | (#40626523)

Chuck Norris streams are streams of pure meaningless bullshit.

Re:Do the same to protons. (1)

marcosdumay (620877) | about 2 years ago | (#40628289)

Proton streams?

They have a couple of those at the LHC. They even cross the streams. Twice.

Perfect (1)

dohzer (867770) | about 2 years ago | (#40624237)

I notice that it is a NEAR perfect stream. Would the perfect stream consist of only particles and no waves?

Re:Perfect (2)

Doc Ruby (173196) | about 2 years ago | (#40626521)

It would consist of no particles or waves. A dark matter smoke ring would do the trick.

Unit of measurement (1)

Bromskloss (750445) | about 2 years ago | (#40624299)

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?

Re:Unit of measurement (2)

Grishnakh (216268) | about 2 years ago | (#40625079)

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 length of this exotic metal alloy rod" to "the distance of x number of wavelengths of some radioactive emission". I haven't read TFA (it's slashdotted).

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? If that's too big, we still have femtoamps which are 1000 times smaller. But if that's not what the article says, then it's really a moot point.

As for the editors, I wonder that all the time. Between the horrible article summaries and the frequent slashdupes, they don't really seem to do much besides click "ok", and really don't deserve the title "editor". Of course, if you look at modern mainstream "journalism" these days, it's not much different. Spelling and grammar errors and terrible writing are commonplace these days in professional publications.

Re:Unit of measurement (2)

psmears (629712) | about 2 years ago | (#40627175)

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 purposes today, but there are limits to the precision that can be achieved in an experiment that measures current using mechanical forces. If it's now practical to create a stream of precisely counted electrons, then we can define the Coulomb and Ampere directly in terms of numbers of electrons, which then has the potential of being much more precise.

So the value of the Ampere and Coulomb won't change (or at least, not significantly), because any new definition will be chosen to be consistent with the old one—but the way we pin down their meaning may do.

Re:Unit of measurement (1)

Grishnakh (216268) | about 2 years ago | (#40628737)

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.

Re:Unit of measurement (1)

CrimsonAvenger (580665) | about 2 years ago | (#40629397)

much like they changed the definition of the meter many years ago from "the length of this exotic metal alloy rod" to "the distance of x number of wavelengths of some radioactive emission".

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.

Not as perfect... (-1)

Anonymous Coward | about 2 years ago | (#40624303)

...as the stream of cum I shot all over your mom's face last night!

that's right bitch, your mom is my slut cunthole

Re:Not as perfect... (0)

Anonymous Coward | about 2 years ago | (#40625207)

Gosh. That was offensive.

1A = 6.241x10^18 electrons/second (4, Informative)

RichMan (8097) | about 2 years ago | (#40624417)

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.

Re:1A = 6.241x10^18 electrons/second (2)

TheRealMindChild (743925) | about 2 years ago | (#40624651)

I doubt the applications are about powering a motor so much as moving data with less need for error correction

Re:1A = 6.241x10^18 electrons/second (2, Informative)

Anonymous Coward | about 2 years ago | (#40625125)

Your house service is AC at a nice integer frequency, so you end up with 0 electrons per second.

Re:1A = 6.241x10^18 electrons/second (1)

martas (1439879) | about 2 years ago | (#40627879)

Yeah but once you plug in that AC/DC converter, all hell breaks loose!

Re:1A = 6.241x10^18 electrons/second (1)

Doc Ruby (173196) | about 2 years ago | (#40626503)

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.

Re:1A = 6.241x10^18 electrons/second (0)

Anonymous Coward | about 2 years ago | (#40629079)

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.

You're correct, but I'd like to point out that even in a DC current the electrons hardly move. It's like waves on the ocean, where the molecules of water just move back and forth as the wave passes. A change in voltage propagates in copper at 95% the speed of light, but the electrons hardly move in the process.

Re:1A = 6.241x10^18 electrons/second (0)

Anonymous Coward | about 2 years ago | (#40627187)

I'll bet if I ran 200A through my hose it would get all black, crunchy and would smoke. Not only would it no longer be any good for the whacking you mention, but my wife would be annoyed on those few instances where she wants to use it.

No no no no! (0)

Anonymous Coward | about 2 years ago | (#40624475)

Didn't you morons listen! I said i need a battery that puts out 19 electrons per microsecond. NOT 14. its not the same. it wont work!

Nice. Closer to absolute measurements. (5, Informative)

Animats (122034) | about 2 years ago | (#40624887)

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. (4, Interesting)

walshy007 (906710) | about 2 years ago | (#40625019)

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]

Re:Nice. Closer to absolute measurements. (1)

aXis100 (690904) | about 2 years ago | (#40625543)

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.

Re:Nice. Closer to absolute measurements. (1)

walshy007 (906710) | about 2 years ago | (#40625865)

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.

Re:Nice. Closer to absolute measurements. (1)

marcosdumay (620877) | about 2 years ago | (#40628343)

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.

Re:Nice. Closer to absolute measurements. (0)

Anonymous Coward | about 2 years ago | (#40629379)

which of the 28 isotopes will be used? just whatever's found lying about?

Re:absolute measurements. NOT REALLY. (0, Insightful)

Anonymous Coward | about 2 years ago | (#40625035)

Not really, bud. The fact that they've made it possible to count individual electrons is certainly nothing new. The notion of coupling one of these things to your household electrical devices to achieve more precise counts of the electrons passing through them is similar to using a laboratory scale at the store to weigh bananas. You don't NEED that much precision when you're talking about that much mass. Similarly, you don't need to know the exact number of electrons passing into and out of your washing machine, it's enough to know how many Watt-hours it uses in a cycle.

This technology will doubtless have applications, but to use it in the home as an alternative to your ammeter is kinda absurd. Might as well try to measure your children's heights to the picometer. It's pointless. As for the notion of redefining the amp, it's silly. The ampere already measures coulombs per second past a point in a circuit. If you have a device that can count up to about a billion electrons per second, there's no need to go inventing a new unit of current measure, you can just say the device passes 10^9 eps. As long as you make sure everyone reading what you wrote or listening to you knows that eps is "electrons per second" you're good.

If you don't like it, because you don't like dealing with numbers that big, there is an easy alternate solution. Just say "electrons per nanosecond". In the case of this pump, it's around 1. Problem solved. Let's not start making new units for no good reason. Amperes work just fine, thanks.

Re:absolute measurements. NOT REALLY. (0)

Anonymous Coward | about 2 years ago | (#40625235)

Arf?

Re:absolute measurements. NOT REALLY. (1)

locofungus (179280) | about 2 years ago | (#40625379)

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.

Re:absolute measurements. NOT REALLY. (1)

benthurston27 (1220268) | about 2 years ago | (#40625717)

An amp is 6.24150965(16)×10^18 (1 coulomb) electrons flowing past a point in one second.

Re:absolute measurements. NOT REALLY. (1)

locofungus (179280) | about 2 years ago | (#40628397)

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.

Re:absolute measurements. NOT REALLY. (0)

Anonymous Coward | about 2 years ago | (#40625393)

You got it all wrong. An Ampere is not defined as a Coulomb per second. A Coulomb is defined as an Ampere second. That begs the question, what is an Ampere? Well, it's based on force and hence dependent on the definition of the kilogram. Kilograms are not properly defined based on fundamental and measurable properties. This is important. Imagine a scenario where all the standard kilograms were destroyed, or just unavailable. Maybe you need to make a standard kilogram on another planet but don't have the original for reference. How do you do it? A good definition of units would be reproducible anywhere in the universe. It would be ideal to have a definition of the Ampere that wasn't dependent on the kilogram. Redefine the Ampere as x number of electrons per second. We can't do that until we can accurately measure how many electrons there are supposed to be in an Ampere. The second is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom. This definition is completely useless if you can't measure that radiation precisely. Therefore, they didn't come up with this definition until after they could count that radiation precisely. This definition is not dependent on the behavior of Earth. It works equally well on every other planet. It will work until the end of time, assuming the laws of physics don't change. If we made contact with aliens, we should be able to tell them what an Ampere is without having to ship them a standard kilogram.

Re:absolute measurements. NOT REALLY. (2)

Doc Ruby (173196) | about 2 years ago | (#40626477)

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 differences when the kilogram and the sampler are accelerating relative to each other, which even thermal jiggling can achieve in significance at these tiny mass differences.

Now that we've identified the Higgs boson, we'll learn more about the Higgs field, and learn to measure mass at extremely precise degrees. The "standard" kilograms' measured mass will be seen to fluctuate both over time and among the standard samples by several orders of magnitude (or rather "minitude" ;).

I hope these new quantum experiments at nanoscale (and even femtoscale) give us fundamental measures that count tiny things (including energy cycles) like "electrons per coulomb" from the bottom, rather than statistically survey large things like kilograms and scale down. Both for the more precise and reliable measurements, and to study the tiny deviations among previously believed "identical" particles like electrons. I expect different quantum states of the same particle type will have different masses due to different energy levels among the states. Perhaps we'll establish reliable equivalencies between information and mass, an "E=mc^2" for "joules per iota". And perhaps due to other factors yet undetermined, like perhaps energy in entanglement, or perhaps other "subquantum" effects yet unobserved until our measuring devices are more precise than the variations in their states.

Re:absolute measurements. NOT REALLY. (0)

Anonymous Coward | about 2 years ago | (#40626937)

Not sure why "identical" is in quotes. Electrons are identical. The identical-ness of fundamental particles has important and measurable results for QM and especially entropy in QM and Stat. Mech.

Re:absolute measurements. NOT REALLY. (1)

Doc Ruby (173196) | about 2 years ago | (#40634439)

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.

Re:absolute measurements. NOT REALLY. (1)

Doc Ruby (173196) | about 2 years ago | (#40626485)

Picograms per bonghit?

Re:absolute measurements. NOT REALLY. (0)

Anonymous Coward | about 2 years ago | (#40627315)

No one is saying this should be installed in household electronics or that it will replace other kinds of ammeters in most applications. It won't even replace ammeters used in most science labs either, in the same way that redefining the second didn't replace timing elements with atomic clocks in most applications. That is not how metrology is handled in most science or day-to-day work.

A few researchers who need extreme accuracy at an appropriate scale might switch over to devices that directly measure the quantity a unit is defined in terms of. Everyone else, uses some other device. If they still need accuracy, they send their devices off to other people who calibrate it for them. The people who calibrate the equipment do so by comparing the equipment's measurements to a more accurate device. That more accurate device might be calibrated by some other team/company that does a better job, but ultimately at some level there is a company that compares equipment calibration to the standard (or a few weird cases, like when voltage was calibrated against Josephson junctions instead of standards for other base units).

The point is not to replace your pocket sized digital ammeter with something the size of a room. The point is to make make calibration of things like the digital ammeters easier and more reliable. To trace an ampere calibration back to a standard at this point requires, at some level, someone to use a watt balance, which is a real pain to use for such purposes. If instead it can be shown that there are reliable ways of counting large number of electrons, even at picoamp levels, as long as you can then work out a calibration of ampere level equipment from a chain of equipment/calibrations that is more reliable than the watt balance, the definition of an ampere can be changed. That would probably involve defining the charge of an electron to be an exact value (at the moment, the charge of the electron is a measured value, so its uncertainty would factor into trying to calibrate current measurement based on counting electrons).

404 on the link (0)

Anonymous Coward | about 2 years ago | (#40625669)

The link to the article is bad.

Energy of Spin? (1)

Doc Ruby (173196) | about 2 years ago | (#40626415)

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? (1)

Life2Death (801594) | about 2 years ago | (#40626611)

We can make better displays with this right - now one electron wide pixels!

Re:Better displays? (0)

Anonymous Coward | about 2 years ago | (#40626975)

Um....I do get this was a weak attempt at a joke, but I don't think you know what electrons are. I also doubt very much you know what light is.

As an exercise, just try to find the "width" of an an electron. Then try to understand why you couldn't find an answer.

For part B, please try to understand why you also can't have a pixel smaller than the wavelength of the color you're trying to view.

It really is amazing how much ignorance you compressed into such a short statement.

Re:Better displays? (0)

Anonymous Coward | about 2 years ago | (#40628259)

As an exercise, just try to find the "width" of an an electron. Then try to understand why you couldn't find an answer.

Maybe something roughly on the order of h/p ...

For part B, please try to understand why you also can't have a pixel smaller than the wavelength of the color you're trying to view.

You could have a pixel smaller than the wavelength. It won't really be resolvable in the far field, but could be useful for near field stuff. So a TV resolution enjoyable only by microbes and microscopists.

Re:Better displays? (0)

Anonymous Coward | about 2 years ago | (#40630743)

Maybe something roughly on the order of h/p ...

The debroglie "wavelength" of an electron? That has nothing to do with the size of an electron, and since p is directly proportional to velocity, you'd be saying an electron at rest has infinite size. It's just not the right concept. I can calculate the debroglie wavelength of your body travelling in a car and I'd come up with something much, much smaller than you really are. There is no meaningful correlation between size and debroglie "wavelength".
 

You could have a pixel smaller than the wavelength. It won't really be resolvable in the far field, but could be useful for near field stuff. So a TV resolution enjoyable only by microbes and microscopists.

You can not view something smaller than the wavelength of light being used to view it. This applies to microbes, microcopists, and everything else in the universe. For one thing if you could get around that fundamental limit, you overthrow the heisenberg uncertainty principle and with it most of quantum physics. Microscopists can use higher energy waves and other techniques but the concept becomes meaningless for trying to view electrons/photons emitted from a screen. It's equally meaningless to try and see a picture printed on a page, since the molecules that make up the dye must be larger than electrons.

Re:Better displays? (0)

Anonymous Coward | about 2 years ago | (#40631525)

The debroglie "wavelength" of an electron? That has nothing to do with the size of an electron

It is one of the potential limiting factor of the resolution of electron optics (kind of ignoring some other limits from space charge, electron optic aberrations, and source quality, which keeps resolution maybe a factor of 20 above diffraction limit). The resolution limits of electron optics is really the only size relevant to such an application, in the same way you are talking about the limits of photon resolution without needing to argue various meanings of size of a photon.

You can not view something smaller than the wavelength of light being used to view it. This applies to microbes, microcopists, and everything else in the universe.

As I referenced in the previous post, you should look into Near Field Optics [wikipedia.org] . Quite a few techniques, such as a near field scanning optical microscope [wikipedia.org] can resolve things unlimited by the diffraction limit. Currently resolutions have been achieved that are a factor of 20-100 times smaller than the wavelength of the visible light being used. Of course this requires close contact with such a screen, but the uselessness of such a screen to anything other than a microbe on the screen or a microscopist was already addressed. (On a more serious level, such a screen may have uses for various forms of fluorescence microscopy or stuff like structured illumination microscopy, assuming it were actually practical.)

I've got a good name (2)

slashmydots (2189826) | about 2 years ago | (#40627339)

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.

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 (1)

Khyber (864651) | about 2 years ago | (#40629651)

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.

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