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General => General Discussion => Topic started by: Sketchy on January 03, 2013, 12:26:30 PM
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https://www.nature.com/news/quantum-gas-goes-below-absolute-zero-1.12146
It may sound less likely than hell freezing over, but physicists have created an atomic gas with a sub-absolute-zero temperature for the first time1. Their technique opens the door to generating negative-Kelvin materials and new quantum devices, and it could even help to solve a cosmological mystery.
So, for all you other physicists out there... Have fun.
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No way. Reading it. No way.
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That's really cool if it's true.
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That's really cool if it's true.
Well, it's not a supposition, is an experimental evidence. And it's on Nature. So, it's true :)
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Yeah, but what does this have to do with the price of coffee in Bhopal?
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It's "sup, we broke science", not "sup, we broke economics" I'm afraid.
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It's "sup, we broke science", not "sup, we broke economics" I'm afraid.
This is as exciting as superluminal neutrinos. The sexy thing is that this actually exists :D
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Thought this was going to be a thread about my high school girlfriend Lea's heart.
Carry on.
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I thought this is a well-known fact.
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I thought this is a well-known fact.
Why? I had never heard of the theoretical premises behind this experiment. They were not really mainstream.
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I thought this is a well-known fact.
Yea, I've also already heard of an experiment (in Germany, I think?!) where scientists brought an unknown mass to below absolute zero and found a new state of aggregation (Bose-Einstein condensate?!)...........
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I thought this is a well-known fact.
Why? I had never heard of the theoretical premises behind this experiment. They were not really mainstream.
Well, I even knew this when I was at high school. It was theoretical knowledge or not back then but I recall that it was learned in physic lessons. And when I was at university and still of course I learned it is the fact. My speciality is not physic but I did take lessons, read articles. So I thought, at least university students were aware of that.
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BE Condensates happen just above absolute zero, as far as I have always been aware. They happen when the atoms start moving so slowly that the wave functions (as all particles are also waves) start to overlap (or something like that, they get big, basically) and the particles start behaving as a quantum-fluid. This is why if a container holding a BEC is not capped, the fluid will flow out through the walls, but it stops the moment you put a lid on.
It also does other funkadelic stuff like having a constant rotation with respect to the universe (this is something that also makes physicists herp their derp a little, see: relativity - ie. this shouldn't be possible by Einstein's work) and other fun stuff. My old physics teacher's uni tutor won a nobel for his work with helium at almost 0K temperatures, and she got him to do a lecture for us, but that was five or so years back. His name was Anthony something-or-other, he's getting on in years now. But yeah, BECs happen near zero, but this is the first sub-zero thingybob.
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Cool.
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Thought this was going to be a thread about my high school girlfriend Lea's heart.
Carry on.
I was gonna use my ex wife as an example, but the joke has been used now. Damn you!!!!
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That's crazy.
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what the hell. Further proof that all theories in science can be thrown away at some point.
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That's really cool if it's true.
it's not just cool ...
It's Sub-Sub-Zero !
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That's really cool if it's true.
it's not just cool ...
It's Sub-Sub-Zero !
Trent (reading) - The universe is a cold, cold place, black and bleak like outer space. The wind chill drops below subzero, it's not no time to be a hero. (to Max) That doesn't make sense. How can the temperature drop below subzero?
Max - What do you mean? Subzero means below zero.
Trent - That's what I'm saying. If subzero is already below zero, then how can it be below subzero.
Max - Well, that's even colder.
Trent - Even if it's colder, that's still subzero.
Max - Yeah, but Trent, it's the wind chill.
Trent - You see Max, subzero isn't one number, it's all the numbers below zero.
Max - So what?
Trent - So, the temperature can't get below subzero, because no matter how low it gets, it's still part of the subzero set.
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Trent was so awesome. When I saw that episode and and Max's lyrics said "Below sub-zero" I facepalmed, but then Trent schooled him and I was cheering him on.
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That's so difficult to wrap me head around.
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Trent was so awesome. When I saw that episode and and Max's lyrics said "Below sub-zero" I facepalmed, but then Trent schooled him and I was cheering him on.
You mean the wind chill argument didn't sell you?
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This is awesome!
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Trent was so awesome. When I saw that episode and and Max's lyrics said "Below sub-zero" I facepalmed, but then Trent schooled him and I was cheering him on.
You mean the wind chill argument didn't sell you?
Nah. I don't believe in wind chill.
Your cookies are lame
Your chips are the same
You get no respect 'cause
You're not what you claim
Poser exposed!
Hoser de-hosed!
I step on your toes
You're deposed!
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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,
This part makes (absolute) zero sense to me I must confess. You can't have more values above average than below average, because otherwise the average is no longer the average.
I'm not questioning the researchers' result, I just hate it when science reporters just fuddle their way through an explanation.
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Ah, Wikipedia has an entry on negative temperatures:
https://en.wikipedia.org/wiki/Negative_temperature
and this good web page too:
https://math.ucr.edu/home/baez/physics/ParticleAndNuclear/neg_temperature.html
Interestingly, the system isn't colder than absolute zero, but instead hotter than infinite positive temperature. All comes down to the definition of temperature really.
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You can't have more values above average than below average, because otherwise the average is no longer the average.
You're thinking of the median, not the mean. With the mean, one value on either side can offset several on the other, if the difference is extreme enough. I still remember having to learn median, mean, and mode, and how they're all "averages" in different contexts, although the mean is what most people assume when you just say "average".
That said, I agree that their explanation sounds pretty BS to me.
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You can't have more values above average than below average, because otherwise the average is no longer the average.
You're thinking of the median, not the mean. With the mean, one value on either side can offset several on the other, if the difference is extreme enough. I still remember having to learn median, mean, and mode, and how they're all "averages" in different contexts, although the mean is what most people assume when you just say "average".
That said, I agree that their explanation sounds pretty BS to me.
Sorry yeah, it was a rather casual explanation of my complaint. I know it comes down to the "mass" on the left and right of the average, which by definition need to be equal.
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Cool.
Chilling.
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You can't have more values above average than below average, because otherwise the average is no longer the average.
You're thinking of the median, not the mean. With the mean, one value on either side can offset several on the other, if the difference is extreme enough. I still remember having to learn median, mean, and mode, and how they're all "averages" in different contexts, although the mean is what most people assume when you just say "average".
That said, I agree that their explanation sounds pretty BS to me.
Sorry yeah, it was a rather casual explanation of my complaint. I know it comes down to the "mass" on the left and right of the average, which by definition need to be equal.
I figured as much. But since we're being all scientific here, we might as well get the mathematics terminology down, too.
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Aaaaaand, my brain hurts.