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Amazing Quantum Levitation Demonstration Video

  1. Oct 19, 2011 #1
  2. jcsd
  3. Oct 19, 2011 #2
    weird. what's it doing, becoming some kind of semipermanent magnet?
     
  4. Oct 20, 2011 #3
    That was really weird. I have no idea what's going on there.
     
  5. Oct 20, 2011 #4

    ZapperZ

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    I still wonder why they call it "quantum levitation".

    Zz.
     
  6. Oct 20, 2011 #5
    Here's a brief description of how it works:

    "A single crystal of sapphire wafer is coated with a thin ceramic material called yttrium barium copper oxide. The ceramic layer has no interesting magnetic or electrical properties at room temperature, but when cooled below -185ºC (-301ºF) the material becomes a superconductor. It conducts electricity without resistance, with no energy loss.

    Superconductivity and magnetic field do not like each other. When possible, the superconductor will expel all the magnetic field from inside. This is the Meissner effect. In this case, since the superconductor is extremely thin, the magnetic field DOES penetrates. However, it does that in discrete quantities called flux tubes.

    Inside each magnetic flux tube superconductivity is locally destroyed. The superconductor will try to keep the magnetic tubes pinned in weak areas. Any spatial movement of the superconductor will cause the flux tubes to move. In order to prevent that the superconductor remains “trapped” in midair."

    http://unknownskywalker.tumblr.com/post/11641560352/quantum-levitation-a-single-crystal-of-sapphire

    So it isn't just a magnetic effect, but a superconducting quantum effect on the magnetic field.
     
  7. Oct 20, 2011 #6
    I know what you're saying, but it just sounds better than "superconducting yttrium barium copper oxide" ;)

    "Quantum" makes it news worthy.
     
  8. Oct 20, 2011 #7
    This is awesome. After watching this I can't help buy wonder how one could get their hands on some YBCO.
     
  9. Oct 21, 2011 #8

    f95toli

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    Nice demonstration of flux pinning.
    But the fact that the guy kept referring to it a "quantum locking" (or whatever it is he said) annoys me...
     
  10. Oct 21, 2011 #9
    agree...people like using the word 'quantum' where they can for media embellishments :-)
     
  11. Oct 21, 2011 #10

    FlexGunship

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    Usually I can instantly spot the difference between science and bunk... but... uh... I'm torn!

    "Superconductivity?" Got it!
    "Messier Effect?" Rock on!
    "Yttrium barium copper oxide?" Um, yeah, okay.
    "Ceramic coated crystal?" Uhhh...
    "Flux tubes?" No, no, no, no...
     
  12. Oct 21, 2011 #11
    Substance
    Too much colour blinds the eye,
    Too much music deafens the ear,
    Too much taste dulls the palate,
    Too much play maddens the mind,
    Too much desire tears the heart.
    In this manner the sage cares for people:
    He provides for the belly, not for the senses;
    He ignores abstraction and holds fast to substance.
    Lao Tzu
     
  13. Oct 21, 2011 #12

    FlexGunship

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    Oh okay, I get it now. Thanks. :confused:
     
  14. Oct 21, 2011 #13

    f95toli

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    I am not sure what you are refering to, wuliheron's description was pretty accurate.
    Yttrium Barium Copper Oxide (YBa_2Cu_3O_(7-delta), or YBCO for short) is a very common superconductor, which as it happens is also a ceramic material and obviously an oxide.

    "Flux tubes" are more or less "concentrated flux" which occur due to flux quantization in superconductors and -in this case- have the shape of tubes, these tubes do not move easily (they are "pinned") which is why the YBCO is stable when levitating (you can also have things like flux pancakes).
    If you want to read up on the physics of this you should look up Abrikosov Vortices.
     
  15. Oct 21, 2011 #14
    Which equations draw the magnetic field lines connected with the flux tubes?
     
  16. Oct 21, 2011 #15

    DaveC426913

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    The big question is: can I get one in time for Christmas to put next to my Levitron?
     
  17. Oct 22, 2011 #16
    if i'm interpreting this correctly, the individual "flux tubes" will have rings of current superconducting around them. so you've got a bunch of localized superconducting electron donuts that lock in place, right?
     
  18. Oct 22, 2011 #17
    No wonder why superconductivity is one of the most difficult and profound areas of physics to understand.
     
  19. Oct 22, 2011 #18
    I was reading last night and...

    The magnetic field lines are entering the Abrikosov vortices - miniature supercurrents (suppercurrent cells) around the non-superconducting impurities in a very thin, type 2 superconductor. Here, the flux lines form a "flux tube". The flux tubes are difficult to displace in any direction in space, so the superconductor is trapped, locked by the magnetic field.

    The size of a single vortex is about the coherence length (a kind of correlation length) of the given superconductor. The vortex is bound by the London penetration depth - the size to which the magnetic field can penetrate near the surface of a superconductor. The superconductors tend to remove all field lines from their insides by means of resistance-free supercurrents that flow in the presence of the field.

    So, the point is that the superconductor possesses the particular microscale structure built from vortices of supercurrents.

    When you attempt to move the superconductor, there is a minute difficulty followed by a stable, fixed position in the magnetic field. This property is periodic in space, probably in relation with the distinctiveness of individual flux tube positions.

    [This is from wikipedia, with the imagination filling in for the most part.]
     
  20. Oct 22, 2011 #19

    ...And, after some more reading, this is not entirely good. The problem is in "impurities". The Abrikosov vortices of supercurrents are associated with the flux tubes. Imagine a small, round chunk of impurity present to the side of a vertically positioned flux tube. If you try to move the flux tube (by moving the magnet) to the side and across the impurity, the flux tube bends elastically and defies such change for a brief while, as if it could not go through the impurity.
     
  21. Oct 22, 2011 #20

    OmCheeto

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    As I was sitting on my quantum throne a few weeks ago, I was contemplating how to explain to Arcananoir how a similar thing could be possible.

    https://www.physicsforums.com/showpost.php?p=3523118&postcount=1266

    Visions of translational magnetic flux fields generating toroidal electric fields which in turn generated still more complex magnetic flux fields saturated my brain. I decided that only RonL could imagine such complexity. I gave up.

    Interesting that it's the 100 year anniversary of it's discovery, and we're still scratching our heads. :smile:

     
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