Absolute Zero
- Thread starter Orleander
- Start date
There ye GOETH. Asinus ad lyram
If you want to get esoteric about it, fine, but our common understanding and intuition about negative absolute temperatures is correct.
http://istd.gsfc.nasa.gov/cryo/introduction/neg_Kelvin.html
This sort of very specialized situation describes an abstract concept based on "population inversions" that I don't fully understand myself. It really has nothing to do with actual temperatures in normal systems.
This model even includes "infinite temperature" which, if you think about it, is physically impossible due to relativistic limitations (can't really have atoms moving infinitely fast, can we?).
I think he meant the 5th state of matter - Bose–Einstein condensate.
Hmm... Ok?
Right.
OK, so do any of you think Wolfgang Ketterle will eventually get absolute zero? I mean he got 810 trillionths of a degree above it.
Or, that is as close as we would ever want to come?
(and I am not understanding how he made the BEC at all. I mean really? Its not a gas, liquid or solid??? WTHell?!)
Or, that is as close as we would ever want to come?
(and I am not understanding how he made the BEC at all. I mean really? Its not a gas, liquid or solid??? WTHell?!)
No, theoretically you can get very, very, very close, but not 0,000..., not in this universe at least.
At 170 nanokelvin atoms no longer behave like individual atoms, but due to quantum effects behave like one uniform wave. Fascinating really. There is nothing other like that in nature or in our human experience.
BBC has a documentary "The race to absolute zero", you might want to see it.
http://www.mininova.org/tor/864833
But I don't understand why?!
Hang on everybody. Reality check.
You cannot even theoretically reach absolute zero because of a very fundamental feature of quantum mechanics. The uncertainty principle states that you can never obtain both the position and momentum of a particle to arbitrary precision simultaneously. The very act of pinning down one attribute (say momentum) means that you cannot know the position of the particle at all, and vice versa. This is a consequence of the fact that quantum particles really are more of a probabilistic combination of these attributes (and other quantum numbers like spin). By pinning down one precisely, the other goes out the window so to speak and becomes completely indeterminate.
So, true absolute zero implies that you would know the momentum of a particle (or a group of them) as being exactly zero, and the exact positions of the particles. This is a no-no. Not allowed. Can't do it.
You cannot even theoretically reach absolute zero because of a very fundamental feature of quantum mechanics. The uncertainty principle states that you can never obtain both the position and momentum of a particle to arbitrary precision simultaneously. The very act of pinning down one attribute (say momentum) means that you cannot know the position of the particle at all, and vice versa. This is a consequence of the fact that quantum particles really are more of a probabilistic combination of these attributes (and other quantum numbers like spin). By pinning down one precisely, the other goes out the window so to speak and becomes completely indeterminate.
So, true absolute zero implies that you would know the momentum of a particle (or a group of them) as being exactly zero, and the exact positions of the particles. This is a no-no. Not allowed. Can't do it.