New state of matter: Efimov state

[5614]

In 1970 a Russian scientist, Vitaly Efimov, proposed a new state of matter. Only now has this state been confirmed to exist.

 

What is the Efimov state (quote World Science):

Borromean rings. The symbol of the medieval Borromeo family, these rings were so intertwined that removing any one caused the entire structure to fall apart. Physicists use the term to describe some atomic nuclei, because if any one constituent is removed, the rest of the nucleus disintegrates. In a new state of matter, atoms themselves form into structures of this nature.

 

If one of the rings (or in the Efimov state, an atom) is picked up the others will follow. But if one ring (or atom) is removed the structure will fall apart (or repel). This quantum mechanical effect only occurs at a billionth of a degree above absolute zero, previous experiments carried out at a millionth of a degree failed because it was too hot!

 

World Science: http://www.world-science.net/otherne...ewstatefrm.htm

 

Science Daily: http://www.sciencedaily.com/releases...0315174950.htm

[dkv]

How many new states of matter are possible?

[bascule]

The center portion of that shape has significance to the Celts as well, in the form of the Triquetra:

 

[swansont]

In 1970 a Russian scientist' date=' Vitaly Efimov, proposed a new state of matter. Only now has this state been confirmed to exist.

 

...

 

If one of the rings (or in the Efimov state, an atom) is picked up the others will follow. But if one ring (or atom) is removed the structure will fall apart (or repel). This quantum mechanical effect only occurs at a billionth of a degree above absolute zero, previous experiments carried out at a millionth of a degree failed because it was too hot!

 

World Science: http://www.world-science.net/otherne...ewstatefrm.htm

 

Science Daily: http://www.sciencedaily.com/releases...0315174950.htm

 

The linked summaries are sketchy and almost content-free, since they don't describe the experiment and focus on the BS like Borromean rings. ("they observed the state in a vacuum chamber at a frigid minus 459.6 degrees Fahrenheit. That’s equivalent to a billionth of a degree above “absolute zero,” the coldest temperature that can exist." is just plain bad science journalism)

 

Anyway, the Nature paper is a letter (i.e. very short), so it refers to other papers for a lot of details, and I haven't read those yet. Basically they adjusted the scattering lengths with a magnetic field (avoiding the Feschbach resonances), and this works with Bosons, so the "you can do this with any particle" appears to be a little misleading. They were only able to observe one of the resonances.

 

I didn't see a case made for a "new state of matter." It's a weakly-bound trimer, formed under conditions where a dimer is just barely not forming a bound state. It looks like they observed the states by looking at losses from the BEC or cold ensemble that was formed (they did preparation two different ways, one using a BEC and another using the atoms before they collapsed into a BEC) so there was no investigation into the properties of the molecule. Maybe that's written up elsewhere.

 

It's not accurate to say it only works at a nanoKelvin — the effect was also seen at 200 - 250 nK, and fizzles out at about 500 nK.