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New Nanodevice Creates a Near Perfect Electron Stream
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 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.
But my electron pump isn't that precise...
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
#t33 h33 lol#
The last sentence was literally one of the stupidest things I've ever read here.
"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.
Too bad no one seems to be able to use this technology to make a Moray Valve (link).
Can any science/physics gurus tell me what sort of practical applications this has?
We focus protons the same and we can start catching some ghosts.
Who you gonna call? SCIENCE!
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.
I notice that it is a NEAR perfect stream. Would the perfect stream consist of only particles and no waves?
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?
Swedish plasma phys. PhD student; MSc EE; knows maths, programming, electronics; finance interest; seeks opportunities
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.
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!
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.
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.
Gosh. That was offensive.
Arf?
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.
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.
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.
The link to the article is bad.
An amp is 6.24150965(16)×10^18 (1 coulomb) electrons flowing past a point in one second.
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.
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.
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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 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.
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Picograms per bonghit?
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We can make better displays with this right - now one electron wide pixels!
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.
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).
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!
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?
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.
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.
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.
Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
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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