What exactly happens at Absolute Zero

[linux kid]

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

 

[PhanthomJay]

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]

...thanks for the question!

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

 

[ranger]

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]

anymore thoughts on this?

 

[Tzemach]

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 traveling at C.

 

[sanman]

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]

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 occurred 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 occurred 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]

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]

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]

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

 

[chroot]

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.

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

- Warren

 

[Ki Man]

It's impossible to stop an electron's 'motion' around an atom. we can't 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 can't think of an electron like a ball going in a circular orbit. it doesn't even act like matter half the time. i suggest you watch http://dadattack.castpost.com/520670.html"

 

[linux kid]

It's impossible to stop an electron's 'motion' around an atom. we can't 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 can't think of an electron like a ball going in a circular orbit. it doesn't even act like matter half the time. i suggest you watch http://dadattack.castpost.com/520670.html"

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

 

[Ki Man]

the case is still open. it opens a new door in the fronteir of sub atomic physics. we don't know if electrons are solids or waves and what makes them do the things they do

 

[linux kid]

wow, this is amazing. So my question can't 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.

 

[chroot]

wow, this is amazing. So my question can't fully be answered until the electron form is found I guess.

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

 

[ZapperZ]

wow, this is amazing. So my question can't fully be answered until the electron form is found I guess.

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

But for now I will have to assume electrons are not affected by external temperature.

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.

 

[linux kid]

Why do you think the resistance increases with increasing temperature?

this brings me to another one of my questions. But this would make for a good thread.

 

[Danger]

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.Zz.

Love your spelling, dude.
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?

 

[ZapperZ]

Love your spelling, dude.

That's why I didn't become a "spelling major", especially when my fingers and my brain don't work all the time. Still, with all the amount of crap that I've typed, I'm surprised I don't make even more bad spelling and bad grammatical errors.

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?

This is now a different scenario than the electrostatic potential due to an atom. Your scenario cannot be described by a typical "electron in a central potential" problem. It may require other types of interactions involved to describe it accurately, namely the weak interaction. You'll notice that it requires a change in "flavor" of quarks for a proton to turn into a neutron. It isn't just a matter of a simple capture.

This is now a totally different process in which the "atomic picture" no longer applies. So the energy consideration has to be re-evaluated for a totally differnet problem.

Zz.

 

[Danger]

That's why I didn't become a "spelling major"

You'll notice that it requires a change in "flavor" of quarks for a proton to turn into a neutron.

I didn't know any such thing. No high-school diploma, remember...
I'd love to hear more about that, but I don't know that I could understand it.

 

[Ki Man]

http://nobelprize.org/educational_games/physics/matter/10.html"

its amazing how simple things are once you get smaller and smaller

 

[marlon]

I didn't know any such thing. No high-school diploma, remember...
I'd love to hear more about that, but I don't know that I could understand it.

Hey man, this is not high school stuff, trust me

Here is more : Neutron stars are stars that result from the implosion of a very heavy star. Such neutron stars have masses around 1.5 times the mass of the sun. The implosion happens because there is a mass known as the "Chandrasekhar mass", beyond which electron degeneracy pressure cannot hold a star up from gravity. Hence gravity becomes stronger then the counter-acting electron pressure and the star implodes. This mass is around 1.4 times the mass of the sun. Once it's passed (thus, during the implosion), the electrons and protons undergo inverse beta decay and form neutrons. This leads to a star that is instead held up by neutron degeneracy pressure, called a neutron star. There is also a mass beyond which neutron degeneracy pressure will fail and the object will collapse to a black hole.

Beta plus decay commonly means the basic process p->n + e+ + v. It is a nuclear decay mode in that it can only happen if the proton is inside a heavier nucleus and the final state nucleus is more tightly bound. The process is forbidden in free space by energy conservation since a neutron alone is heavier than a proton so you need more "surrounding" energy at the proton side of the energy equation.

Like ZapperZ said : the conversion from neutron to proton or from proton to neutron is the result of the weak interaction. For example, in "ordinary" negative beta decay we get the opposite of the plus beta decay : a neutron decays into a Proton + Electron + Neutrino. This is a particle decay mode. The weak force converts a down quark to an up quark (ie changes the quark flavour) which changes the neutron into a proton.

regards
marlon

 

[moe_3_moe]

hey zz u look so educated or let's say well informed ...
hey linux kid ...first try toi visit the colorado university site and search about the bec...they have the main site about it ... now about the subject that electron will not be affected by the temperature ... we are studying now semiconductors ... and u should know linux that energy level are effected by temperature ... and energy level are specified by the electrons... so in a way temperature affect the electron...try to search about fermi energy level and conduction band and valence band...u can get some formulas relationg the energy levels with the temperature ...hope i helped in a way

 

[ZapperZ]

hey zz u look so educated or let's say well informed ...

I fool many people like that. I am truly a dumb moron.

now about the subject that electron will not be affected by the temperature ... we are studying now semiconductors ... and u should know linux that energy level are effected by temperature ... and energy level are specified by the electrons... so in a way temperature affect the electron...try to search about fermi energy level and conduction band and valence band...u can get some formulas relationg the energy levels with the temperature ...hope i helped in a way

I have to correct this or else someone might understand this differently.

The "energy levels" are not affected by temperature. These energy levels are solution to the Hamiltonian. They do not shift, at least not for reasonable temperature change, unless there is a change in charge carrier density associated with that temperature change. What does change with temperature is the amount of thermal broadening of these states and band. The edge of the conduction band at the Fermi energy, for example, will develop a 'tail' extending above this level as temperature rises. however, unless there is an addition or depletion of charge carriers into the conduction band, the Fermi energy doesn't change.

One can see the same thing when looking at the bands using technique such as core level photoemission. The "sharp peaks" indicating where each band or energy levels are do not shift when you increase the temperature - they only broaden.

Zz.

 

[moe_3_moe]

thermal broadening ??core level photoemission??
i think u r right ... about the energy level i missed this point ... i know it but i did described wrong ...wat are this 2 terms can i have a little idea about them?

 

[moe_3_moe]

thermal broadening means i think that the energy levels will be far from each other?

 

[mgervasoni]

I have a question, and please be nice as I am a new lover of physics:

As I understand:
1: The Bose-Einstein Condensate says the passage of light / photons can slow down at very low / near absolute 0 temperatures.
2. Einstein's theory of relativity states that the speed of light is the constant of the universe, not space or time or space-time, as Newton assumed.
Questions 1:
What happens inside this slowing of the passage of light in relation to (space)time? If we could slow down light, say, all around us, what would be happening?


Question 2:
Is reaching absolute 0 impossible, or possible but we haven't figure out how yet?

 

[mgervasoni]

Isn't a free electron, electricity (electric current)?