Scientists Chill Atoms to Negative Temperatures

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Ukomba:

Redingold:

Ukomba:

My thinking too. However, I'm not sure what the properties of this 'negative' heat substance is, or how, once negative, it gets heated up. If, after crossing the barrier, it stays there, it is possible that a closed system with it could lower entropy. Don't really know enough about it yet.

Nonononono. This thing does not have negative heat, it has negative temperature. Heat and temperature are not the same thing, though they may seem that way in common usage. Heat is just transferred energy, temperature takes account of both energy and entropy. The entropy is what they fiddled with to get negative temperature, not the heat.

I understand that. What I mean is, if you put a colder 'negative' substance (Someone needs to think of a name for it) in a closed system with a hotter normal substance. If the negative substance retains it's properties of decreasing entropy as it's temperature increases, and all it's other properties are that of a normal substance, the total entropy of the total system would decrease. The normal substance would loose entropy as it cooled, and the negative substance would loose entropy as it is heated. The net result being a loss of entropy.

This is all hypothetical since there isn't a lot of information yet.

On a side note, if it's temperature was hot enough it's order could increase to the point where it solidified. The result could be a crystal with a massive amount of energy.

According to the article, if this comes into contact with a positive temperature system, heat flows out of the negative system and into the positive one. Don't ask me to elaborate on that, because I can't.

The Escapist write-up doesn't really do a good job summarizing the actual article (no offense to Jonathan Bolding intended...)

Below is an excerpt from the original article that explained it better (at least for me). Figured I'd share.

In summary, by cooling a group of atoms as close to Zero Degrees Kelvin as possible and then tinkering with the other factors in the Ideal Gas Law (PV=nRT)that are related to temperature, they achieved a negative temperature state with their control group. Pretty slick!

From the original article :

"To generate negative temperatures, scientists created a system where atoms do have a limit to how much energy they can possess. They first cooled about 100,000 atoms to a positive temperature of a few nanokelvin, or billionth of a kelvin. They cooled the atoms within a vacuum chamber, which isolated them from any environmental influence that could potentially heat them up accidentally. They also used a web of laser beams and magnetic fields to very precisely control how these atoms behaved, helping to push them into a new temperature realm.

Because temperature depends on how much atoms move - how much kinetic energy they have. The web of laser beams created a perfectly ordered array of millions of bright spots of light, and in this "optical lattice," atoms could still move, but their kinetic energy was limited.

Temperature also depends on how much potential energy atoms have, and how much energy lies in the interactions between the atoms. The researchers used the optical lattice to limit how much potential energy the atoms had, and they used magnetic fields to very finely control the interactions between atoms, making them either attractive or repulsive.

Temperature is linked with pressure - the hotter something is, the more it expands outward, and the colder something is, the more it contracts inward. To make sure this gas had a negative temperature, the researchers had to give it a negative pressure as well, tinkering with the interactions between atoms until they attracted each other more than they repelled each other.

'We have created the first negative absolute temperature state for moving particles,' said researcher Simon Braun at the University of Munich in Germany. "

Viva Deutschland!

Redingold:

Ukomba:

Redingold:

Nonononono. This thing does not have negative heat, it has negative temperature. Heat and temperature are not the same thing, though they may seem that way in common usage. Heat is just transferred energy, temperature takes account of both energy and entropy. The entropy is what they fiddled with to get negative temperature, not the heat.

I understand that. What I mean is, if you put a colder 'negative' substance (Someone needs to think of a name for it) in a closed system with a hotter normal substance. If the negative substance retains it's properties of decreasing entropy as it's temperature increases, and all it's other properties are that of a normal substance, the total entropy of the total system would decrease. The normal substance would loose entropy as it cooled, and the negative substance would loose entropy as it is heated. The net result being a loss of entropy.

This is all hypothetical since there isn't a lot of information yet.

On a side note, if it's temperature was hot enough it's order could increase to the point where it solidified. The result could be a crystal with a massive amount of energy.

According to the article, if this comes into contact with a positive temperature system, heat flows out of the negative system and into the positive one. Don't ask me to elaborate on that, because I can't.

Perhaps it requires not thinking about it as a transfer of energy, but entropy. If a positive substance has lower entropy than it steals than it adds entropy to it until they're balanced. That's what happens in normal mater. In this case, though, it would mean that if you pored an positive energy glass of water into a bucket of negative water at the same temperature, one of them would boil away into steam while the other freezes into ice until the entropy levels of both substances were the same.

You have no idea how much this concept excites me. It's just... Wow.

Yo, dese atoms iz chill! Werd.

Aside; I cannot see this being a commercially viable means of energy efficiency anytime soon. Hybrids, for example, are not as profitable as pure fossil fuel cars, so companies that profited on gasoline sales want to start taxing mileage just to make up the difference. Nikola Tesla is another example of greed gone wrong, if I understand the story correctly. All I am saying is that too many companies will simply never allow an unprofitable thing like this see major commercial usage. I can at least see military applications or developing nations (maybe).

Go home science, you're drunk.

To be honest, I feel like this has more to do with our definition of temperature not being as simple and concrete as we often imagine than some sort of bizarro-world heat.

the reverse entropy thing is insane though, if that's true this has to be the single biggest discovery in the history of science ever.

Negative temperature? It's so cold it started vibrating backwards?

elilupe:
I love how none of this actually makes any common sense. They have found a way to get past absolute zero without hitting it, it gets hotter than positive numbers could get, and it could lead to more than 100% efficient machines.
I love science.

LOL! I was thinking exactly the same things as I read the article!

I hope this turns out to be mostly true and just effectively making energy a free resource.

Ickabod:
Wait. Doesn't this violate the laws of thermodynamics?

SCIENTIFIC PROGRESS CARES NOT FOR YOUR PUNY THERMODYNAMICS!

Vegosiux:

elilupe:
I love how none of this actually makes any common sense. They have found a way to get past absolute zero without hitting it, it gets hotter than positive numbers could get, and it could lead to more than 100% efficient machines.
I love science.

I'm pretty sure the issue is with interpretation, not the experiment itself.

But the thing is, "temperature" is basically defined as the kinetic energy of the particles. And therefore, the lowest possible temperature is the one where the particles are not moving at all. You can't "cool an atom below absolute zero", at least not if you still want to keep the same definition of "temperature" as we use when we say "Oh, it's 23 degrees outside".

Oh and why does this suddenly come to mind?

Bottom line...the scientists themselves don't know what exactly they have discovered so they'll look into it further while the media sensationalizes and misinterprets the research results. Nothing new.

Nothing to see here, citizen, move along.

PS: Not saying that we're never, ever, going to redefine "temperature". Science does redefine stuff to fit with empirical results. But, the current definition of temperature simply does not allow negatives.

It's probably a misquote, I imagine they meant to say 100% more efficient engines, not engines with over 100% efficiency, different concepts. The former is twice as efficient as a current engine, the latter produces more energy than you put in XD.

Ickabod:
Wait. Doesn't this violate the laws of thermodynamics?

No, it means that thermodynamics is breaking the law of thermodynamics.

Let's see if I can put my (mostly earned. One more semester to go) physics degree into use.

I'm going to ignore the fact that it's "colder than absolute zero" because by definition that's impossible. I'm going to attribute that to media sensationalism.

Particles sharing energy states when they normally shouldn't? Well that's breaking a law we thought immutable. Interesting.

Now, normally entropy increases as you put heat into a system as the particles are able to exist in a larger number of energy states (more energy means more possible energy states avalible). Here, with the particles sharing the highest energy state, entropy actually decreases. This... well this changes things a lot. A system must always exchange energy sutch that the total entropy increases, so it will expel heat to outside substances, like any hot material does.

Now the article has made it seem like they achieve this state of matter by cooling it past some kind of breaking point. If that is true... well this is going to be incredible!

Capcha: good job

Well thanks Capcha! I did do my best!

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