Slashdot Mirror

← Back to Stories (view on slashdot.org)

Physicists Watch Individual Electrons Flow

Posted by ryuzaki0 on from the going-with-the-flow dept.

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."

6 of 120 comments (clear)

  1. So... by RyanFenton · · Score: 4, Interesting

    Would it have to change the flow by measuring it? How much by pure quantum "observation" effects?

    As a non-phyisics grad (Computer science), I'm wondering.

    Ryan Fenton

  2. Current, tunneling ? by karvind · · Score: 5, Interesting
    I RTFA and it employs two quantum dots to distinguish the direction of the flow. As the article mentions: scientists already know how count single electrons travelling through an individual quantum dot

    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.

    1. Re:Current, tunneling ? by XchristX · · Score: 2, Interesting

      There would have to be some sort of "effective quantum impedance" (for want of a better phrase) of the contact which can be adjusted such that the device sees a very small input impedance so that the device does not measurably affect the source.

      --
      l'Homme n'est Rien l'Oeuvre Tout: Gustave Flaubert to George Sand
  3. So does this mean... by Audent · · Score: 2, Interesting

    that we can finally see just what happens with that light box experiment with waves/particles of light?

    Someone with a clue help me out here. Does this mean we'll get a definitive answer on how a single particle of light can actually be in two places at once?

    --
    I am a leaf on the wind
    1. Re:So does this mean... by Memnos · · Score: 5, Interesting

      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.
    2. Re:So does this mean... by moosesocks · · Score: 2, Interesting

      My education on these matters is sadly limited (for now), but I'm not quite so sure they're "almost there", or if they'll ever be "there" for that matter.

      Any observation of a quantum particle requires some sort of interaction with that particle. Once you interact with the particle, the wave function collapses.

      Unless I'm horribly mistaken, this breakthrough only allows us to observe particles with less interaction to them. Regardless of this fact, any observation imlies a collapse of the wave function. Einstein proved this IIRC.

      From what I understand, until *any* given phenomena is observed, it is occupying all possible states of being. Once it is observed, the probability function collapses, and it settles on one state of being. This manifests itself particularly well in the double slit experiment, because, the particle has a 50% chance of hitting one slit or the other, and as long as you don't make any observations before the particle hits the slit(s), it seems to pass through *both*. Of course, the definition of "observation" is pretty broadly defined as any interaction with just about anything.

      Perhaps someone with more knowledge can comment. (It's not like any of this is even relevant anymore anyhow..... Bistromathematics will soon replace quantum physics. )

      --
      -- If you try to fail and succeed, which have you done? - Uli's moose