# A "New" State of Matter

Someone explain to me how *an ulta-cold gas is a new state of matter. Hadn’t anyone ever heard of liquod nitrogen before?

IANAPhysicist (though I play one on TV) so I am ignorant on this subject, so, in laymans terms please, what did these guys do to win themselved the Nobel Prize.

Knowledge of Bose-Einstein condensation earns bonus points

Well liquid nitrogen is a liquid, a rather ordinary and common state of matter at appropriate temperature and pressure.

The Bose-Einstein condensate is a more exotic state like plasma that doesn’t exist under except under special conditions. Even plasma isn’t all that exotic, arc welders create it every day.

The difference between this and liquid or vapor nitrogen is the radically different physical properties you get in a Bose-Einstein condensation. Cold nitrogen gas behaves exactly like you’d expect a gas to behave. A Bose-Einstein condensation doesn’t act like a gas, so it’s a new state.

I just got back from a class that was about Eistein-Bose condensates.

The slim skinny is that what we are looking at is an weird property that particles get when we lower the temperature enough so that we send the guys to their groundstates (that is, the lowest energy state they can be in). This isn’t just cold… liquid nitrogen is a furnace for this stuff… at least for now.

The properties of this type of matter is extraordinary, but there are many websites out there that will do better justice to it than I. Go google!

So which is it: Bose-Einstein condensate or Einstein-Bose condensate? We seem to have it both ways here.

And why can’t we just call it “cold plasma”?

Usually termed “Bose-Einstein”. S.N. Bose first developed the mathematical theory predicting its existance, but his work only applied to photons. He sent his ideas to Einstein, who worked up the predictions for other particles.

Because a Bose-Einstein condensate is different from plasma. Plasma is a gas where the electrons have been stripped from the atoms. You can do interesting things with this, but the atoms are still separate entities. A BEC works differently. All the atoms in the condensate lose their “identity”, if you will, and act as if they were one atom. The laws of quantum mechanics are more important here than classical, Newtonian physics. I’m grossly oversimplifying, of course. See micco’s links for more.

I listened to a news report about this over the radio this morning. The interviewee mentioned possibly using this new state of matter like a laser beam, except with more accuracy. Can anyone elaborate?

Better than laser beams with regards to measurement. One way of looking at is to say that the particles in this particular state have very low entropy… low enough to be able to serve as guideposts for measurements that would be done. It is always tricky to try to establish standard “meter sticks” in the lab. This state of matter fits the bill better than the previous worker of wonders, the single frequency photon beam (laser).

Slight Nitpick…

Plasma is far from exotic. IIRC of all matter in the universe well over 90% of it is plasma. So, in reality, the state of matter you and I are in is more exotic than plasma is.

In fairness, however, I will say that on earth plasma is extremely rare. Sure you can get some easily enough (in plasma displays for instance or those lightning globes) but you don’t run across it much just out in the open.

Travel to the sun and you can find a whole lot of it.

Yeah, but go at night when it’s safer.

Yesterday morning, I attended a lecture by William Phillips, who won the Nobel in physics in 1997 for his work in using laser light to cool atoms. He was going to talk about his own work, but when the prize was announced, he changed his topic to Bose-Einstein condensates. The room was full of high school physics students, so I could follow along.

He had plenty of liquid nitrogen to throw around, and a Levitron to illustrate the principles of magnetic traps–he even had a video of Ketterle (one of yesterday’s winners) using the Levitron, in case he couldn’t get the Levitron to work himself.

He showed graphs of the velocity distribution of the atoms in the magnetic trap that eventually became the condensate, which appeared on the cover of Science five years ago, I think. They showed typical bell-shape curves at 400 nanodegrees (less than one millionth degree) but a sharp spike at zero when the temperature lowered to 50 nanodegrees. The atoms of the Bose-Einstein condensate were not moving relative to each other.