Scientists Get Below Absolute Zero

[Gahars]

Absolute Zero is supposed to be the absolute coldest temperature there is. You just can't go any lower than that. Pretty simple, right?

Well, apparently no one defined "absolute" to a group of German scientists, who took on the age-old question of "How cool is cool?" for themselves.

Schneider and his colleagues reached such sub-absolute-zero temperatures with an ultracold quantum gas made up of potassium atoms. Using lasers and magnetic fields, they kept the individual atoms in a lattice arrangement. At positive temperatures, the atoms repel, making the configuration stable. The team then quickly adjusted the magnetic fields, causing the atoms to attract rather than repel each other. “This suddenly shifts the atoms from their most stable, lowest-energy state to the highest possible energy state, before they can react,” says Schneider. “It’s like walking through a valley, then instantly finding yourself on the mountain peak.”

At positive temperatures, such a reversal would be unstable and the atoms would collapse inwards. But the team also adjusted the trapping laser field to make it more energetically favourable for the atoms to stick in their positions. This result, described today in Science1, marks the gas’s transition from just above absolute zero to a few billionths of a Kelvin below absolute zero.

Nature

Huh. Looks like Lord Kelvin's getting the cold(er) shoulder.

Sure, it's only a few billionths we're talking about here, but as far as "temperature limbo" goes, that's still an amazing breakthrough. They shimmied below a threshold that was supposed to be absolute, after all.

This isn't some useless endeavor, either. The techniques and results could be turned towards creating new types of matter in the laboratory, and could theoretically play a role in the development of quantum devices. Plus, since the behavior of sub-absolute zero gas seems to mimic that of so-called "dark energy", it could help us better understand this mysterious force.

Needless to say, these guys shouldn't have their assets frozen anytime soon.

So the next time you're caught out in the cold, freezing and miserable, just remember that it could always be colder; science is making sure of that.

 

[Devin]

Hey ladies? What's cooler than being cool?

ICE COLD.

 

[iluvfupaburgers]

science still keeps surprising me somtimes. great breakthrough

 

[Rizsparky]

'COOL' story bro.

 

[lismati]

Gahars surely used his pun limit up on this one.

 

[bowser]

Well, sometimes getting less than zero is a good thing.

 

[Tom Bombadildo]

That's pretty cool. In fact, that's cooler than absolute zero.

 

[Bladexdsl]

is it cold in here or is it just me?

 

[SifJar]

Very interesting and impressive achievement.

Something of note for everyone making "cool" and "cold" jokes though; the absolute negative temperature is actually hotter than an infinite positive temperature. It's called negative because it's an inversion of the positive Boltzmann distribution. So your puns are invalid

 

[Hells Malice]

I'm not sure what the story is about anymore, but there's glass and shattered things all around my desk and my forehead is bleeding.

I blame puns.

 

[nukeboy95]

that cool

 

[chavosaur]

This is really neat, I love when scientists shatter what was thought to be certain.

 

[nando]

how do they measure something below absolute zero?

 

[Celice]

My guess is it has something to do with the signature above you :o

 

[VMM]

how do they measure something below absolute zero?

-x number K(or ºC or ºF)

 

[Psionic Roshambo]

What I want to know is how do you get below absolute zero.

Since absolute zero is the absence of any molecular motion.

To put it another way, its like saying a stopped car is now moving even slower than stopped.

I think we are being trolled by scientists... lol

 

[Gahars]

For all the people asking, the article explains a bit more on how the scientists accomplished this feat - it was just excised from the post to fit in more puns make the quote more concise.

Lord Kelvin defined the absolute temperature scale in the mid-1800s in such a way that nothing could be colder than absolute zero. Physicists later realized that the absolute temperature of a gas is related to the average energy of its particles. Absolute zero corresponds to the theoretical state in which particles have no energy at all, and higher temperatures correspond to higher average energies.

However, by the 1950s, physicists working with more exotic systems began to realise that this isn't always true: Technically, you read off the temperature of a system from a graph that plots the probabilities of its particles being found with certain energies. Normally, most particles have average or near-average energies, with only a few particles zipping around at higher energies. In theory, if the situation is reversed, with more particles having higher, rather than lower, energies, the plot would flip over and the sign of the temperature would change from a positive to a negative absolute temperature, explains Ulrich Schneider, a physicist at the Ludwig Maximilian University in Munich, Germany.

 

[spinal_cord]

Less than no energy?!!

 

[Wizerzak]

@The comments about negative temperature, well quite simply:

Essentially negative temperature here refers to a thermodynamic property of the system that is perhaps divergent from the ordinary definition in this case. Temperature here defines therate at which entropy increases as thermal energy is added to the system. Ergo, negative temperature relates to a state where adding energy at least incrementally might decreasethe entropy of the system.
Link to comments in article

So.. yeah...

 

[Bladexdsl]

that's a ICE explanation