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Mon Jan 7, 2013, 08:45 AM

Absolute zero temperature barrier breached by scientists with interesting implications

http://www.sciencedaily.com/releases/2013/01/130104143516.htm

Jan. 4, 2013 What is normal to most people in winter has so far been impossible in physics: a minus temperature. On the Celsius scale minus temperatures are only surprising in summer. On the absolute temperature scale, which is used by physicists and is also called the Kelvin scale, it is not possible to go below zero at least not in the sense of getting colder than zero kelvin.

According to the physical meaning of temperature, the temperature of a gas is determined by the chaotic movement of its particles the colder the gas, the slower the particles. At zero kelvin (minus 273 degrees Celsius) the particles stop moving and all disorder disappears. Thus, nothing can be colder than absolute zero on the Kelvin scale. Physicists at the Ludwig-Maximilians University Munich and the Max Planck Institute of Quantum Optics in Garching have now created an atomic gas in the laboratory that nonetheless has negative Kelvin values. These negative absolute temperatures have several apparently absurd consequences: although the atoms in the gas attract each other and give rise to a negative pressure, the gas does not collapse a behaviour that is also postulated for dark energy in cosmology. Supposedly impossible heat engines such as a combustion engine with a thermodynamic efficiency of over 100% can also be realised with the help of negative absolute temperatures.

In order to bring water to the boil, energy needs to be added. As the water heats up, the water molecules increase their kinetic energy over time and move faster and faster on average. Yet, the individual molecules possess different kinetic energies from very slow to very fast. Low-energy states are more likely than high-energy states, i.e. only a few particles move really fast. In physics, this distribution is called the Boltzmann distribution. Physicists working with Ulrich Schneider and Immanuel Bloch have now realised a gas in which this distribution is precisely inverted: many particles possess high energies and only a few have low energies. This inversion of the energy distribution means that the particles have assumed a negative absolute temperature.

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Arrow 20 replies Author Time Post
Reply Absolute zero temperature barrier breached by scientists with interesting implications (Original post)
stevenleser Jan 2013 OP
dipsydoodle Jan 2013 #1
AngryAmish Jan 2013 #13
dipsydoodle Jan 2013 #15
Ikonoklast Jan 2013 #2
Recursion Jan 2013 #3
Fumesucker Jan 2013 #7
Xipe Totec Jan 2013 #4
kentauros Jan 2013 #9
TheMadMonk Jan 2013 #10
kentauros Jan 2013 #12
JoeyT Jan 2013 #16
kentauros Jan 2013 #17
TheKentuckian Jan 2013 #14
Victor_c3 Jan 2013 #5
Saboburns Jan 2013 #6
Recursion Jan 2013 #8
Sirveri Jan 2013 #18
Make7 Jan 2013 #11
Brother Buzz Jan 2013 #19
Odin2005 Jan 2013 #20

Response to stevenleser (Original post)

Mon Jan 7, 2013, 08:54 AM

1. Cool

No pun intended.

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Response to dipsydoodle (Reply #1)

Mon Jan 7, 2013, 10:30 AM

13. yet it was achieved.

bravo

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Response to AngryAmish (Reply #13)

Mon Jan 7, 2013, 11:14 AM

15. Read some of the comments in the earlier post in the Science forum.

.

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Response to stevenleser (Original post)

Mon Jan 7, 2013, 09:03 AM

2. Whoa. Achieveng better than 100% thermodynamic efficiency is almost as good as perpetual motion.

The next century will be interesting, once we break our shackles to last century thinking.

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Response to stevenleser (Original post)

Mon Jan 7, 2013, 09:06 AM

3. This would have huge implications for information theory...

...since a Boltzmann crystal at 0K has 0 entropy. If it could have negative entropy, then we have a true information sink.

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Response to Recursion (Reply #3)

Mon Jan 7, 2013, 09:34 AM

7. Fox News viewers don't count?



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Response to stevenleser (Original post)

Mon Jan 7, 2013, 09:06 AM

4. Now all we need is a nice hot cup of tea to make an infinite improbability drive. nt

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Response to Xipe Totec (Reply #4)

Mon Jan 7, 2013, 09:44 AM

9. I thought that was a piece of fairy cake?

And the proper thinking of improbability added

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Response to kentauros (Reply #9)

Mon Jan 7, 2013, 10:00 AM

10. No you need the tea to create it. The fairy cake to run it. /nt

 

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Response to TheMadMonk (Reply #10)

Mon Jan 7, 2013, 10:29 AM

12. Okay, it's been a while since I read the book.

I only knew that "fairy cake" was used somewhere in it.

What is fairy cake, anyway?

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Response to kentauros (Reply #12)

Mon Jan 7, 2013, 01:49 PM

16. A cupcake.

I looked it up right after I read that book.

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Response to JoeyT (Reply #16)

Mon Jan 7, 2013, 02:15 PM

17. Must be a British thing

like "biscuits" for cookies.

I wonder what they think of the "fairy cake" craze in the states right now...?

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Response to Xipe Totec (Reply #4)

Mon Jan 7, 2013, 10:32 AM

14. I think that is the Bistromath Drive

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Response to stevenleser (Original post)

Mon Jan 7, 2013, 09:17 AM

5. Pushing the limits of gods creation...

This can't be a good thing. When god created us 6,000 years ago I don't think he intended us to do this.

Look out for the next super-storm or sinkhole. There'll be divine retribution for this - I'm sure.

(I hope you guys can pick up on my sarcasm)

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Response to stevenleser (Original post)

Mon Jan 7, 2013, 09:31 AM

6. How can something have negative kinetic energy??

Temperature is a measure of kinetic energy, at absolute zero there zero kinetic energy.

But, how can something have negative kinetic energy??

I don't get it.

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Response to Saboburns (Reply #6)

Mon Jan 7, 2013, 09:40 AM

8. The definition of temperature is based on atoms being billiard balls

Since they instead occupy a range of states among several probability distributions, you can get weird stuff like that (from the article, you get negative absolute temperature by, oddly enough, superheating gas).

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Response to Saboburns (Reply #6)

Tue Jan 8, 2013, 12:32 PM

18. the strange thing is negative potential energy which is seen in bound nucleons.

So it's possible... I guess. If you hit the 'I believe' button.

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Response to stevenleser (Original post)

Mon Jan 7, 2013, 10:24 AM

11. NOVA did an interesting episode called 'Absolute Zero' five years ago.

It was two parts, so it's about an hour and forty five minutes. There is a long history on the quest of scientists to reach lower and lower temperatures - it becomes really interesting when they get to temperatures where the normal properties of matter break down and weird things start to happen.

The full program is on YouTube:

http://www.youtube.com/watch?v=y2jSv8PDDwA


Or if you want to skip ahead to where I think it starts to get really interesting:

http://www.youtube.com/watch?v=y2jSv8PDDwA#t=4458s

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Response to stevenleser (Original post)

Tue Jan 8, 2013, 12:51 PM

19. On another front, faster-then-light neutrinos have been debunked by physicists

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Response to stevenleser (Original post)

Tue Jan 8, 2013, 12:52 PM

20. My brain hurts now.

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