what does /sci/ think of this?
Old article, but it states that a laboratory has managed to create a gas with a temperature in "negative Kelvin".
This means below 0 Kelvin, which makes no sense to me because I thought temperature was measured according to particle movement and 0 Kelvin means no movement... the article doesn't do much justice in explaining the concept very well.
It has to do with population inversion. If I have more excited states than ground states, I have achieved negative absolute temperatures. So, all laser pointers achieve negative absolute temperatures since lasing requires a population inversion.
It's more of a definition thing and makes sense in that regard.
We have never even reached 0 K. And if we did, we could not go into negative temperatures by decreasing the temperature even further.
>I thought temperature was measured according to particle movement and 0 Kelvin means no movement.
That's not what 0 Kelvin means, FYI. Matter at 0 K would still be moving around. It would just be unable to lose any more energy. "No movement" is physically impossible.
Ususally you hear of temperature as a measure of movement/jiggling. However, temperature is defined as:
1/T = dS/dE
As in, how much more disordered/mixed up does a system get when I pump in some energy? Turns out that some systems get less disordered when you pump in more energy, which gives a negative temperature.
It's a bit far away from what you conventionally think of as temperature, you could say it's autistically following the definition wherever it goes. Which is strangely how much of physics works.