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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."
Here's a picture of the ammeter in action.
So now ol' Ben Franklin can finally see which direction electrons really flow!
Just because it can't be explained doesn't mean it isn't true. Science fits into reality... not the other way around.
My question is if I want to measure current (assume an ideal current source) then I will hook it up to this new invention. The mechanism of current in this new measuring device is quantum tunneling. Is there any reason that the current source in question employs the same mechanism. It may still be conventional drift-diffusion with very very low fields (and probably very low mobility). Now when I interface it with this double-quantum device, does the change in mechanism ensures current quantity ? If answer yes, what is the intutive answer. I can understand current continuity when it is drift and diffusion.
Before you read any of the article and just say the headline: "Physicists Watch Individual Electrons Flow" did anyone think of a bunch of guys in white lab coats looking down at a table with money in their fists betting on electron races? Because I did... And boy was it disturbing... Gambling physicists can be very rude. (At least the ones in my head are)
Eating the brains of your enemies does not make you smarter. But it's still fun.
We already know the answer to that. "Wave propagation" and "particle interaction" are redundant expressions; "wave interaction" and "particle propagation" are oxymoronic. "Waves" and "particles" are not entities or properties but rather behaviors - wave propagation is the constant or increasing lack of information about the quantum relative to the observer/instrument/indicator and particle interaction is the creation or transmission of information relative to the observer/instrument/indicator.
Single particle interactions are never in two places at once. The information that originally was one quantum may be distributed across space as it propagates as a wave or distributed across ensembles of different quanta in entangled states, but the interactions (particles) themselves are always strictly local.
"Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?" - Patrick Henry
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.
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
I think that a plausible explanation (or at least one that deserves more research) is the Pilot Wave theory proposed by de Broglie-Bohm. See http://plato.stanford.edu/entries/qm-bohm/ and other numerous sites for a discusion of this proposition. (Disclaimer: I have never been a big fan of the Copenhagen Interpetation.) Nonetheless, I feel that an explanation which obviates the "observer problem" and explains decoherence merits looking at.
I don't trust atoms -- they make up stuff.