Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

What exactly happens at Absolute Zero

  1. Jan 4, 2007 #1
    I understand atoms stop moving, but do electrons also stop orbiting? Absolutely everything freezes?
     
    Last edited: Jan 5, 2007
  2. jcsd
  3. Jan 4, 2007 #2

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    You can't get to absolute zero, only pretty darn close. So there is always some motion. I suggest you do a google search on "Bose-Einstein Condensate". Very interesting to see what happens at near 0 degrees absolute, I think it might be like several millionths of a degree above 0, as I recall, I'll think i'll check it myself, thanks for the question!
     
  4. Jan 4, 2007 #3
    I think this is my best question so far. Learning is fun! o:)
     
  5. Jan 4, 2007 #4

    ranger

    User Avatar
    Gold Member

    Electrons will not stop orbiting nor will everything "freeze". This is because it will violate the Heisenberg uncertainty principle, which states that we cannot know the position and momentum of a particle simultaneously. At 0 K, it will simply be at its lowest energy state.
     
    Last edited: Jan 4, 2007
  6. Jan 4, 2007 #5
    anymore thoughts on this?
     
  7. Jan 5, 2007 #6
    A Bose-Einstein Condensate can slow the passage of light. It does not actually affect light the way a gravitational field generates a redshift it is more a matter of the super dense material adsorbs and re-emits photons in such a way that the photons entering on one side take far longer to arrive on the opposite side than they would travelling at C.
     
  8. Jan 5, 2007 #7
    Hi,

    Bose-Einstein Condensate only occurs with a gas cooled to absolute zero. If you cool a solid, you just have a solid. I once e-mailed Prof Wolfgang Whateverhisname, right after he won the Nobel prize for the BEC, and he actually pleasantly emailed me right back. He told me that BEC's are not ultra-dense but are in fact very low density, due to the fact that they come from a gas phase.
     
  9. Jan 5, 2007 #8

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    This is not quite right because we haven't reached "absolute zero" yet. So the fact that we have already observed BEC implies that it didn't occur at absolute zero.

    Note that the BEC in gasses, where Ketterle, Weiman, and Cornell won the Nobel Prize for occured at around 2 microKelvin. This isn't really "absolute zero". Furthermore, BEC is well-known in fluids, such as liquid Helium, both He4 and He3. Those occured even at higher temperatures than the BEC in gasses. And at the other end, superconductivity is an example of a BEC of composite bosons, which are the Cooper pairs. These can occur as high as 150K!

    So no, BEC does not only occur at absolute zero.

    Zz.
     
  10. Jan 5, 2007 #9
    Non of these directly answer my question. Please someone tell me wheather electrons stop orbiting or slow down rotation.

    Well, OK maybe this question is a little too ambitious since we haven't observed absolute zero. So I will settle with near 0kelvin temps. like liquid helium. What happens there?
     
  11. Jan 5, 2007 #10

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    They will not. The electrons don't "orbit" in the first place. Still, the ground state of an atom is the LOWEST state that the atom can be in. The electrons all simply cannot collapse to a single state and stop moving. Even in a quantum harmonic oscillator, the lowest possible energy available is not zero. This means that the atomic vibration in a solid would never be gone even at T=0.

    Zz.
     
  12. Jan 5, 2007 #11

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Try searching the net for zero point motion. That should throw up a few hundred relevant references.
     
  13. Jan 5, 2007 #12

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    No.

    Electrons, in quantum mechanics, do not orbit like little planets. They don't have a defined speed of rotation at all, so this question has no real answer.

    Perhaps you're talking about Bose-Einstein condensation? I'm going to link to two qualitative explanations of the phenomenon I wrote here a long time ago.

    https://www.physicsforums.com/showpost.php?p=137968&postcount=4
    https://www.physicsforums.com/showpost.php?p=69583&postcount=6

    - Warren
     
  14. Jan 5, 2007 #13
    It's impossible to stop an electron's 'motion' around an atom. we cant reach absolute zero but if we did someone did it, atoms would not move at all (relative to surrounding atoms) but within the atom, functions would continue.

    you cant think of an electron like a ball going in a circular orbit. it doesnt even act like matter half the time. i suggest you watch Dr. Quantum explain matter and electrons
     
    Last edited: Jan 5, 2007
  15. Jan 5, 2007 #14
    that video is awesome but spoooky at the end. did they figure out what it had to do with the observer?:confused: :surprised
     
  16. Jan 5, 2007 #15
    the case is still open. it opens a new door in the fronteir of sub atomic physics. we dont know if electrons are solids or waves and what makes them do the things they do
     
    Last edited: Jan 5, 2007
  17. Jan 5, 2007 #16
    wow, this is amazing. So my question cant fully be answered until the electron form is found I guess.

    But for now I will have to assume electrons are not affected by external temperature.
     
  18. Jan 5, 2007 #17

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Physicists have a very good understanding of the electron; it's not a matter of lack of knowledge. The electron behaves in a way very well described by the most accurate theory currently known to mankind: quantum electrodynamics. It just happens that this theory does not consider electrons to be like tiny planets orbiting stars, as you would seem to prefer. The microscopic world just isn't that way.

    - Warren
     
  19. Jan 5, 2007 #18

    ZapperZ

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    Your question has been fully answered, several times! Just because you won't accept them doesn't mean it hasn't.

    This is also wrong!

    I used to study the properties of electrons in a solid as a function of temperature. We know how they behave VERY well in conventional solids, and they ARE affected by temperatures UNDER MANY CIRCUMSTANCES. The conduction electrons are certainly affected by temperatures due to increase scattering with the lattice ions as you heat up a conductor. Why do you think the resistance increases with increasing temperature?

    But you cannot apply this rule to everything. In an atom, the GROUND STATE is the lowest possible energy that the atom can be in (I could has sworn I have said this already!). The electron in the ground state cannot be forced into any lower state than this.

    These two situations (electrons in metals and electrons in an atom) are two different conditions and are described differently by quantum mechanics. This does NOT mean we know nothing about them. In fact, we know enough that we made use of our knowledge to design the semiconductors that you are using in your computer chips!

    I have no idea what else you want out of your question, even after it has been answered.

    Zz.
     
  20. Jan 5, 2007 #19
    this brings me to another one of my questions. But this would make for a good thread.
     
  21. Jan 6, 2007 #20

    Danger

    User Avatar
    Gold Member

    Love your spelling, dude. :tongue:
    That aside, ZZ, I have a serious question. If the electron is forced into the nucleus to merge with a proton and become a neutron, as in a neutron star, does that represent a lower energy state, or is it a higher one because it's an unnatural condition?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?