Next Physics Nobel- Atoms cooled to negative temperatures

carlazai

carlazai

carlazai

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German scientists (boffins if you are reading the Mail) have cooled atoms to negative temperature i.e. -5K. An area that will not produce results soon but could be an area for superconductors and other temperature sensitive devices.

This was an obvious area that needed more research because any time you hear 'you cant do it' in science is asking for someone to prove what happens if you try.

http://www.escapistmagazine.com/news/view/121377-Scientists-Chill-Atoms-to-Negative-Temperatures
 
Guys as a quantum physicist I can catagorically state that this is both impossible and being terribly reported in the media. In the simplest terms possible temperature only occurs because of the motion of particles in a medium, so for water to have a temperature of 100 degrees Centigrade then the water molecules are moving a lot, and the constituent atoms within are also moving and vibrating massively (I know this as I have simulated water at these kinds of temperatures - I'm sure I could rustle up a video if anyone wants to see it.).

So what that means is that as the temperature reaches absolute zero (so called because it is absolute), the motion of the particles - both in terms of vibrations, and actual motion, must become zero so the particles are frozen in both time and space (Excluding the zero-point energy). Therefore if a temperature is negative then it must imply that the particles are still moving (albeit maybe in a less expected way) but if they are moving then they *must* have a temperature!

HTH

This video should give an idea of what happens even at zero degree C. This is taken using very advanced theories in quantum physics, created by some good friends of mine in the LCN at UCL in London.

 
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Dr Delphi said:
Guys as a quantum physicist I can catagorically state that this is both impossible and being terribly reported in the media. In the simplest terms possible temperature only occurs because of the motion of particles in a medium, so for water to have a temperature of 100 degrees Centigrade then the water molecules are moving a lot, and the constituent atoms within are also moving and vibrating massively (I know this as I have simulated water at these kinds of temperatures - I'm sure I could rustle up a video if anyone wants to see it.).

So what that means is that as the temperature reaches absolute zero (so called because it is absolute), the motion of the particles - both in terms of vibrations, and actual motion, must become zero so the particles are frozen in both time and space. Therefore if a temperature is negative then it must imply that the particles are still moving (albeit maybe in a less expected way) but if they are moving then they *must* have a temperature!

HTH

This video should give an idea of what happens even at zero degree C. This is taken using very advanced theories in quantum physics, created by some good friends of mine in the LCN at UCL in London.

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That's how I understood it as well...

Burnsy2023 said:
I'll believe when I see it in a proper academic journal. And even then I'll be sceptical.
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This and...

Theoretically, this innovation could lead to more than 100% efficient engines
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Erm, perpetual motion machine anyone?
 
Amp34 said:
Erm, perpetual motion machine anyone?
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If you quote, try and quote properly :p He's talking about Heat Engines not any other kinds of engines. Now I've read the description on collapsed wavefuntion (nice blog btw thanks!), I think I understand it some more, and so I stand by the fact that the motion must still be there ergo it not being lower than absolute zero.

However, it is very interesting to see that they have trapped a non-stable state using an optical lattice - interestingly I'm not so sure we could do that in simulation to see if we get the same results.
 
I found a link to their paper: http://www.sciencemag.org/content/339/6115/52

It doesn't make much sense to me. Science is a reputable journal so there's a reasonable chance it hangs together.

Absolute zero is defined in terms of a classical gas - it's not expected to hold together if pushed to extremis. A discontinuous jump to an infinite temperature seems unlikely, but could be a flaw in how the system is defined. An axial compressor acting as a turbine has an infinite efficiency, not because it "breaks the laws of physics!" but because efficiency is defined as the reciprocal of the efficiency of a turbine.
 
Dr Delphi said:
If you quote, try and quote properly :p He's talking about Heat Engines not any other kinds of engines. Now I've read the description on collapsed wavefuntion (nice blog btw thanks!), I think I understand it some more, and so I stand by the fact that the motion must still be there ergo it not being lower than absolute zero.

However, it is very interesting to see that they have trapped a non-stable state using an optical lattice - interestingly I'm not so sure we could do that in simulation to see if we get the same results.
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You're still creating more energy than you put in are you not? That's what more than 100% efficiency means.

(haven't read anything but the original article so...)
 
RomanNose said:
It's only impossible if you misunderstand what temperature actually is.
It's not what they teach you in school.
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This is pretty much what I was taught in GCSE Physics:

Dr Delphi said:
Guys as a quantum physicist I can catagorically state that this is both impossible and being terribly reported in the media. In the simplest terms possible temperature only occurs because of the motion of particles in a medium, so for water to have a temperature of 100 degrees Centigrade then the water molecules are moving a lot, and the constituent atoms within are also moving and vibrating massively (I know this as I have simulated water at these kinds of temperatures - I'm sure I could rustle up a video if anyone wants to see it.).
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From what little I read somewhere (forgot), Apparently this is not your normal negative temperature.

What they did was a trick really, they made the atoms repel each other while they raised their energies from -273 degrees C, forcing them to stick in place, thus an energy distribution that shouldn't make sense.

Perhaps its pointless and just playing around with physics, but perhaps its useful.

I would not say it had anything directly to do with temperature, it simply simulates what it might be like if there were a negative realm to it, from what i can tell anyway.
 
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GeX said:
This needs to posted with a massive disclaimer that it's about entropy, and not hot / cold temperature.

I think this blog explains it better than I can

http://www.thecollapsedwavefunction.com/2013/01/negative-temperature.html
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This is by far the best explanation out of the article posted. Everyone should read this before posting.

And don't stop reading once its explained
heat engines with greater than 100% efficiency (without breaking the laws of thermodynamics
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