Colder than Cold?

news.yahoo.com...

I cannot wrap my head around how it is possible to get atoms to go slower than stopped.

If there is a state lower than the lowest level for an electron, then it wasn't the lowest state right?

That is insane i wonder what will come of this. It could mean engines that work at more than 100% efficiency!

Originally posted by twinmommy38
news.yahoo.com...

I cannot wrap my head around how it is possible to get atoms to go slower than stopped.

If there is a state lower than the lowest level for an electron, then it wasn't the lowest state right?

Mind. Blown.

The part that I found exciting is how the state of this negative temperature could get energy from colder substances as well as hotter ones. My brain really hurts after that read but I understand the implications I think. Awesome find!

reply to post by topherman420


My brain hurts as well

If I understood it right then reversing entropy is possible with the right mechanical set-up.

Something that should be impossible with the current laws of physics.

This is fascinating but like everyone else it's hard to get your head around the fundamental importance of what they've discovered after one reading of an article in yahoo.news.

I'll need to go through it again,take my time and try to absorb it properly because after the initial read it seems like a genuine breakthrough that could change our understanding and lead to technology that probably hasn't been thought possible in practical terms up to now.

Like I said,I want to reread it again because I'm not sure exactly if I've read and understood it properly but it does seem to suggest certain laws of physics are breakable that was thought couldnt be broken,notably entropy !!!

Does that mean the laws of thermodynamics are maybe more fluid than was believed ??

Have I read something in it that it isn't actually saying,have I just got the wrong end of the stick.

i'm not too sure but it sounds like it'll fascinating to find out.

Could this allow advances with super conductors too ??

If energy flows from a particle with negative temperature to pretty much anything, that ought to be a positive feedback loop.

The more energy that flows from it, the more negative its temperature ought to go, absorbing energy from everything around it, eventually dropping other particles nearby below 0K, which will also start doing this.

A sort of thermal black hole. Unless the article writer just got the details wrong, which I could believe.

Perhaps equally interesting - is the claim from the article found at nature.com - which states such cold clouds of atoms could defy gravity, in clouds of normal atoms.

For instance, Rosch and his colleagues have calculated that whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature, some atoms will move upwards, apparently defying gravity4.

I for one love the pace with which science is advancing right now!

Originally posted by twinmommy38
news.yahoo.com...

I cannot wrap my head around how it is possible to get atoms to go slower than stopped.

If there is a state lower than the lowest level for an electron, then it wasn't the lowest state right?

You'd be well served by actually reading the article you linked to. They explain quite clearly what they did and how they did it and it has absolutely nothing to do with going "slower than stopped". They didn't reduce the temperature of the atoms to negative levels, they reduced the temperature of the _GAS_; that is, of the aggregate state of the atoms' arrangements. There's more to temperature than just the kinetic energy of the atoms as the article explained. At great length. For several paragraphs.

Yes, it's a fascinating new state of matter and may let us do/understand a lot of new things -- but it's not like the laws of thermodynamics have changed or anything like that.

reply to post by Stunspot


Quotes from the article:

"An object's temperature is a measure of how much its atoms move — the colder an object is, the slower the atoms are.

When temperatures go either below zero or above infinity on the positive region of this scale, they end up in negative territory.

The inverted Boltzmann distribution is the hallmark of negative absolute temperature, and this is what we have achieved,"


The atoms had to go slower than stopped (below absolute), or be heated above infinity to achieve this. I did read the article and could not fully comprehend it.

You obviously fully understand this subject.

Perhaps you could explain it easier?

reply to post by twinmommy38


Below absolute zero, this is a realm where new whole fields of technology will build upon each other with each advance and each successful experiment. It will be interesting when someone comes to this thread who either understands this data very well or actually worked on the project. Nice thread, thanks.

reply to post by twinmommy38


I'm giving this a bump because of the potential implications and the envelope-stretching reality of the topic.

My understanding of this is that 'negative temperatures' don't give you colder than cold but rather, hotter than hot. The article is mostly a lot of undeserved hype, since this same thing was discovered in 1951 (see: Purcell, E.M.; Pound, R.V, Phys. Rev., 1951, 81, 279 - 280). The methods they used for this (population inversion of states) aren't even novel; the same underlying principles are used in certain types of lasers, for instance (Four-level lasers).