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Physicists Watch Individual Electrons Flow
SG writes "Physicists at the Tokyo Institute of Technology have developed the world's most sensitive ammeter yet. The device allows current to be measured at the attoampere level and is expected to be of use in nanoelectronics, calibration devices, quantum computation and biology."
RTFA.
The device could be used for a wide variety of applications, including nanoelectronics, calibration devices, quantum computation and biology (Science 312 1634).
And that was in the first paragraph. It took you longer to type your post than it would have to actually read the first paragraph. And you even forgot to yell 'frist post.
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
http://www.analogzone.com/tmt_0912.pdf
Except that charge is what's moving, not necessarily electrons.
I think you'll find that the majority of charge carriers are in fact electrons.
No, no, no . They modded it 'informative' as a joke, you understand. Yup. That's Slashdot humor for you. It's subtle. Really subtle.
Try this http://www.vega.org.uk/video/subseries/8. If you don't have the bandwidth you can buy them from the University of Auckland.
I reserve the write to mangle english.
You're talking about the double-slit experiment or two-slit experiment consisting of letting light diffract through two slits producing fringes on a screen. These fringes or interference patterns have light and dark regions corresponding to where the light waves have constructively and destructively interfered. The experiment can also be performed with a beam of electrons or atoms, showing similar interference patterns; this is taken as evidence of the "wave-particle duality" predicted by quantum physics. Note, however, that a double-slit experiment can also be performed with water waves in a ripple tank; the explanation of the observed wave phenomena does not require quantum mechanics in any way. The phenomenon is quantum mechanical only when quantum particles - such as atoms, electrons, or photons - manifest as waves. I doubt the machine will be able to distinguish whether one electron goes through one slit and/or vice/versa. Remember, observing the behavior of these particles causes the wave pattern to collapse. They're almost there, but they're very far off at the same time.
Electrons do move from negative to positive, but the "current" as defined by Ohm's Law does "flow" from positive to negative. Way back when they didnt know which direction stuff moved, so they defined it as moving from positive to negative for the sake of their mathematical calculations. Right hand rule, left hand rule. . bah semantics.
If you are about to mod me down, keep in mind that this post was most likely sarcastic.
Apparantly, it uses quantum effects to do its measurements. There are two very small electron "cages" and the electron must tunnel across from one "quantum dot" (their words) to the other. In answer to your question ALL ammeters affect the systems that they measure. Mostly it isn't a big deal because they have very low resistance. There are some situations where it is very difficult to measure current. One scenario is when the resistance of the circuit is very small. The other is when the current is very small. The reason it is so hard to measure small currents is that there is thermal movements of electrons in the metal. When you amplify the current it amplifies the noise. There are various ways of getting around this. According to TFA this technique introduces very little noise, which allows it to measure very small currents. The whole heisenberg effect is more a matter of indeterminacy for individual particles. The scale of the measurements appear to be big enough that the sum of the individual particles should be an accurate representation of the flow. If anyone reading the article can add clarity, I would welcome it.
If I understand Dirac correctly, his meaning is this: there is no God, and Dirac is his Prophet. -Pauli
You misunderstand what the double slit experiment involves.
In the double slit experiment, the light or particle source that is used is turned down so low that at any given time, there is no more than 1 particle going through the barrier.
This cannot be replicated in a ripple tank. A ripple tank, or any kind of macro scale wave inherently cannot produce the same result as the double slit experiment because it can not be proven that any individual particle is the wave is interfering with itself.
I'm gonna need a spec.
You link looks broken, but this description (where it is called the "Guide Wave Interpretation") points out that it is incompatible with Bell's inequality.
For a pretty thorough discussion of various interpretations, have a look at the containing article.
You will not drink with us, but you would taste our steel? - Walter Matthau, The Pirates