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back to article Boffins create quantum gas with temperature BELOW absolute zero

Boffins at the Ludwig Maximilian University in Munich, Germany have literally turned the Kelvin scale on its head, having produced a quantum gas with a temperature below absolute zero. Ulrich Schneider and his colleagues created the subzero gas by arranging potassium atoms into a lattice using lasers and magnetic fields, then …

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Anonymous Coward

So they have negative Kinetic Energy?

and therefore imaginary speed?

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Coat

Re: So they have negative Kinetic Energy?

No need to get complex…

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Anonymous Coward

Re: So they have negative Kinetic Energy?

Ah...

http://en.wikipedia.org/wiki/Negative_temperature

"negative temperature is a strictly quantum phenomenon"

... hence the mind-fuck

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Negative Kinetic Energy but Positive Virtual Power?*

Methinks, therefore speedy imagination is a leading metadatabase consideration for Novel Mega Kinetic Energy Storages and Hot IP Stores.

For those luscious tales of absolute power beyond earthly control .... Heavenly Trails which Follow Devilishly Good Deeds Done Devilishly Good :-)

Is Kim Dotcom building a Virtually IntelAIgent Power System with Secure Anonymous Programmers Sharing Gathered Key Secrets? Or is that proprietary private information safe and secure in Novel Mega Storage facilities.

Quite what those facilities can and will then do with secured information and advanced intelligence, is the stuff of pure and true legend.

* The Great Military Dilemma .... Peaces Provide Perfect Virgin Power Platforms, and yet the Fooled play War in the Great Games Field.

War is simple. Pick a tall tale and invade. Peace in worlds of endless bounty to enjoy and share appears to present an execution difficulty and identifies a virtual machine malfunction ... and an anomaly which shouldn't really be there. Is human intervention at fault and to blame?

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Re: Negative Kinetic Energy but Positive Virtual Power?*

Weird and askew of the topic as usual but strangely poetic construction. Nice.

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Re: So they have negative Kinetic Energy?

No, they have finally produced LUDICROUS SPEED.

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Headmaster

Re: So they have negative Kinetic Energy?

They appear to have created a quantum of unstable thought on the inside of my head from a considerable distance.

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WTF?

Re: So they have negative Kinetic Energy?

You're quite right.

By redefining absolute zero we have created something below absolute zero.

Balls to 'em. What did they do for new year's 'eve?

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Re: Negative Kinetic Energy but Positive Virtual Power?*

What in the fuck are you talking about? Is that some random word generator??

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Coat

Re: So they have negative Kinetic Energy?

Heading in the right direction, but it really can't be Ludicrous, since that is part of a predictable progression.

This is a strange scale-turns-back-on-itself thing so it must be the next along the scale, genuinely Faster Than Ludicrous, and yet slightly weird at the same time. You know what this means.

A true FTL such as this could only ever be Plaid.

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Re: Negative Kinetic Energy but Positive Virtual Power?*

No, it's the man from mars!

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Happy

Re: So they have negative Kinetic Energy?

First thing I thought on reading the article intro was "aren't population inversions in a laser in a negative temperature state?"

I must get out more.

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T is related to the logarithm of available states

For an isolated collection of atoms behaving as a gas one would be using the so-called "statistical mechanics" formalism for temperature.

I was taught that temperature was related to the change in entropy with energy pumped into the system. You get negative temperature when there's a grossly unlikely set of occupied states. (Entropy of an isolated system is proportional to the logarithm of the available number of states). Much of the math assumes the system is at equilibrium. Apparently these atoms were not. So curious anomalies are possible.

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Re: T is related to the logarithm of available states

What is the answer in double decker bus lanes?

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Boffin

Sci Am had a good article on this 35 years ago

Scientific American

Volume 239, Number 2, August, 1978

"Negative Absolute Temperatures"

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Re: Sci Am had a good article on this 35 years ago

Torrent, please.

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Re: Sci Am had a good article on this 35 years ago

Issues of Scientific American have a page in which they reproduce articles from 25, 50, and 75 years ago... so if you want to read the article mentioned above, all you have is wait until 2028 and buy a copy.

Glad to be of service!

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Unhappy

Re: Sci Am had a good article on this 35 years ago

Well, a have SciAm subscription (okay, I admit they sometimes write bad stuff but their illustrations are the best) but even then their online archive is just 1993 to present....

I AM WAY ABOVE FOURTEEN AND WHAT IS THIS?

Even the IEEE has better archives.

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FAIL

Re: Sci Am had a good article on this 35 years ago

Actually, this was first done in 1951...

So, not actually news then....

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"The temperature scale simply does not end at infinity,"

Surely he means 'zero'? Or do they have other research going on that gets to negative values of temperature by heating something to infinity and beyond?

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Re: "The temperature scale simply does not end at infinity,"

> Or do they have other research going on that gets to negative values of temperature by heating something to infinity and beyond?

That's exactly it.

The Wikipedia article http://en.wikipedia.org/wiki/Negative_temperature has been cited as containing a good introduction.

It is an effect in a quantum system so you need to forget your intuition.

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Pint

Re: "The temperature scale simply does not end at infinity,"

There seems to be no need to invoke THE QUANTUM. See SDoradus above.

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Joke

Re: "The temperature scale simply does not end at infinity,"

Maybe he's using two's complement. You can keep adding until you go negative.

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Re: "do they have other research going on"

Of course they do.

At the Black Mesa facility.

Crowbar mandatory.

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Re: "At the Black Mesa facility."

Ha Ha,

Fat chance!

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Stop

nonsense

Playing fast-and-loose with the definition of temperature with a few hundred potassium atoms balanced on individual laser beams is one thing. Making new and novel stable materials is a whole different bunch of subatomic phenomena.

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Boffin

Re: nonsense

True, but it all has to start somewhere...

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Coat

Pop. Sci headline "Scientists clock the thermometer of the Universe."

Respect.

Time to do the walk of shame.

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This post has been deleted by its author

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Coat

Very cool.

Not really, but I'll grab my coat anyways.

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Facepalm

"below absolute zero"

And I'm still here? Non-story, fellas...

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Re: "below absolute zero"

Heads....

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Boffin

It all depends on how you define temperature

Temperature is a meaningful concept when a system is in equilibrium. The authors of this work pull a fast one by putting the system out of equilibrium and looking at the 'temperature' before the system is equilibrated, hence they can produce this weird property of a negative temperature.

Nice trick, but it's mostly a creative use of scientific language to sell some elaborate experiments to the broader public.

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Re: It all depends on how you define temperature

Exactly. Well Said. Thank You.

Temperature only exists as a meaningful concept when a system of particles are at - or very close to - equilibrium.

This experiment is like sticking all your furniture to the ceiling and saying "Hey! I have produced anti-gravity"!

http://protonsforbreakfast.wordpress.com/2013/01/04/negative-temperatures-do-not-exist/

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Happy

Re: It all depends on how you define temperature

>Nice trick, but it's mostly a creative use of scientific language to sell some elaborate experiments to the broader public.

I think you've concisely defined New Scientist's MO. Good work, sir!

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Well, that merely proves..

.. that nothing is absolute.

Well done - I love it when someone upends established thinking and thumbs his or her nose at tradition.

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Boffin

Looking at the abstract

It appears that they have produced a population inversion, like a laser before it fires.

Except that being in a solid the energized atoms are at different levels above the ground state when they pull their trick, rather than the single one you need for a laser to work.

I suspect SDoradus's description of temperature as it applies to a group of atoms is the correct way to look at this.

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When they "suddenly adjust the magnetic field...."

.... what do they mean by 'suddenly'?

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Re: When they "suddenly adjust the magnetic field...."

I was under the impression that "suddenly" only occurs when you're just walking along minding your own business and not paying attention. In this case however, we're talking science, so it will have a more strict definition - could we perhaps talk of multiple suddenlies, or even 1/2 suddenly?

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Pint

Re: When they "suddenly adjust the magnetic field...."

Suddenly, in this context, is defined as 1 millionth of a perfect pint (The time it takes for a pint of Guinness to settle acceptably)

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Holmes

Understement of the year nominee (already!)

"That might seem counterintuitive at first;"

This is in opposition to all other quantum effects which are intuitively obvious?

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What's new?

There is nothing particularly novel, sinister, or, indeed, special in negative temperatures - they correspond to higher energy states being more populated than low energy ones. Such systems can exist while isolated. Isolation is, of course, difficult to achieve or maintain in an experiment.

For chuckles, I recall (French physicist of Russian/Jewish origin) Anatole Abragam's "model of the Soviet Union" as a system with negative temperature (a notion - in physics - to which Abragam himself contributed significantly). The main point was that as long as such a system is isolated, as the USSR was before Gorby, it can maintain the state. Once brought into contact with a thermostat (outside world) it would transition into a normal, positive temperature state. Formally though, it needs to pass through a state with infinite temperature, i.e., absolute chaos. Anyone remembers what it looked like in the 90ies? ;-)

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Anonymous Coward

Anti gravity

So does this mean I might eventually get the anti grav pack I always wanted since reading about them in Henlien's Starship Troopers when I was a kid?

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Unhappy

Re: Anti gravity

"So does this mean I might eventually get the anti grav pack I always wanted since reading about them in Henlien's Starship Troopers when I was a kid?"

The GI's did not use antigravity.

And no you don't get one because of this research.

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Mushroom

My brain just melted

Why do I persist in reading stuff like this on a Saturday?

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Re: My brain just melted

Crikey, FatGerman, imagine the billions with nothing new to entertain and occupy their thinking. How be their day decided and who delivers fate and destiny and programming to the masses?

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Indeed

I remember that one of my first assignments when taking a Scientific Russian course in 1972 was to translate an article which noted that systems at negative absolute temperatures were the basis of lasers. I assume, though, that the research is new because it involves negative absolute temperatures - hotter than infinity, not colder than zero - in a different kind of quantum system, one where they weren't previously produced.

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Boffin

My Brain Hurts

I hate quantum mechanics.......

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Mushroom

Reminds me of the study...

That assumed on the radiographical analasis (typing in dark here with a no letter keyboard) that the atmosphere would in fact not be set globally on fire, due to atmospheric testing of the Mighty A Bomb.

However in plunging below absolute zero, if THAT ever escapes from the laboratory, it could devastate the entire planet, by flash freezing the entire surface.......

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A Simple Explanation

Think of a plastic cylinder containing marbles.

If it just sits there, they're all at the bottom.

If you shake it back and forth a small distance, the marbles will bounce up and down. The faster you shake it, the more often a marble will hit the top of the cylinder.

You could work out a mathematical formula for how much it's being shook randomly based on the logarithm of the ratio between the density of marbles at the top and bottom. As the amount of random shaking approaches infinity, the number of marbles at the top and the bottom would approach equality.

Now jerk the whole cylinder down quickly instead of shaking it. The marbles will go to the top. So the formula will give a negative logarithm, but that means more than infinite shaking instead of less than no shaking.

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