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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."
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