What exactly happens at Absolute Zero...

**linux kid** · Jan4-07, 11:29 PM

I understand atoms stop moving, but do electrons also stop orbiting? Absolutely everything freezes?

**PhanthomJay** · Jan4-07, 11:36 PM

Originally Posted by linux kid

I understand atoms stop moving, but do electrons also stop orbiting? Absolutely everything freezes?

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!

**linux kid** · Jan5-07, 12:03 AM

Originally Posted by PhanthomJay

...thanks for the question!

I think this is my best question so far. Learning is fun!

**ranger** · Jan5-07, 12:29 AM

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.

**linux kid** · Jan5-07, 12:58 AM

anymore thoughts on this?

**Tzemach** · Jan5-07, 01:11 AM

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.

**sanman** · Jan5-07, 08:04 AM

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.

**ZapperZ** · Jan5-07, 08:16 AM

Originally Posted by sanman

Hi,

Bose-Einstein Condensate only occurs with a gas cooled to absolute zero.

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.

**linux kid** · Jan5-07, 04:17 PM

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?

**ZapperZ** · Jan5-07, 04:20 PM

Originally Posted by linux kid

Non of these directly answer my question. Please someone tell me wheather electrons stop orbiting or slow down rotation.

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.

**Hootenanny** · Jan5-07, 04:23 PM

Try searching the net for zero point motion. That should throw up a few hundred relevant references.

**chroot** · Jan5-07, 04:24 PM

Originally Posted by linux kid

Non of these directly answer my question. Please someone tell me wheather electrons stop orbiting

No.

or slow down rotation.

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.

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?

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.

http://www.physicsforums.com/showpos...68&postcount=4
http://www.physicsforums.com/showpos...83&postcount=6

- Warren

**Ki Man** · Jan5-07, 04:42 PM

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

**linux kid** · Jan5-07, 05:34 PM

Originally Posted by Ki Man

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

that video is awesome but spoooky at the end. did they figure out what it had to do with the observer?

**Ki Man** · Jan5-07, 07:23 PM

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

**linux kid** · Jan5-07, 08:25 PM

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.