"Negative Temperature" Achieved

sanman

I was reading this article which says that scientists have recently achieved a "negative temperature" system, which apparently has a temperature which is "below absolute zero":

http://arstechnica.com/science/2013/...rature-system/

So this seems to get into some legalistic debates on what temperature actually is, and how "negative absolute temperature" is actually hotter than infinitely high temperature, etc. I'm still parsing through it, trying to understand.

What are the practical applications of this, if any?
Could it be possible to use this "negative temperature" to heat up things which are already intensely hot?
Could it be possible to use this to cold down something which is already at absolute zero?

Could we use this to cool electronic or laser components more efficiently?
Could we use this to heat up D-T fuel pellets for fusion?
Could we use it for anything practical?

Drakkith

Maybe. I think it depends on how hot the object already is that you want to heat up further.

I don't think so. First, you can't reach absolute zero. And second, as article states a negative temperature system is already near maximum energy. It can't really absorb more. You would end up heating the material you wanted to cool.

You could heat the pellets up, but D-T fusion pellets require an enormous burst of heating to cause them to implode. I don't see any way to make this work using a physical material to provide the heating. Lasers are used because they can deliver the energy quick enough and evenly enough for the implosion to work correctly.

No idea.

Vanadium 50

There is already a thread on this: http://www.physicsforums.com/showthread.php?t=662268