As always, if you have any questions, feel free to ask.Claus

[slugcountry]

http://www.telegraph.co.uk/earth/ma...&grid=&xml=/earth/2007/12/23/scicosmos123.xml

"Inside the tube an isotope of helium (called helium three) forms a "superfluid", an ordered liquid where all the atoms are in the same state according to the theory that rules the subatomic domain, called quantum theory.

What is remarkable is that atoms in the liquid, at temperatures within a thousandth of a degree of absolute zero, form structures that, according to the team at Lancaster University, are similar those seen in the cosmos. "


****

If it sounds too good to be true... well, is it?

 

[Gokul43201]

All I can say right now, is that the picture with the 2 test tubes made me want to throw up! :yuck:

 

[Astronuc]

But one of the complaints commonly levelled at a leading contender for a "theory of everything", called string theory, is that it is impossible to test.

Hmmmm. According to whom?

"For instance, the internal structure of the superfluid mirrors very closely the structure of space-time itself, the 'background' of the universe in which we live," says Haley.

"Consequently the superfluid can be used to simulate particle and cosmic phenomena; black holes, cosmic strings and the Big Bang for instance.

Well - just don't tell me, show me the proof!

And then there is the notion that there are possibly two dimensions of time??

However, he adds that the team is only assuming there is one dimension of time. Itzhak Bars of the University of Southern California in Los Angeles has put forward the bizarre suggestion that there are two dimensions of time, not the one that we are all familiar with.

Prof Senovilla says: "One thing that is definitely not included in our models is the possibility of having more than one time dimension."

While the theory is outlandish, it is not without support. Prof Gary Gibbons, a cosmologist at Cambridge University, believes the idea has merit. "We believe that time emerged during the Big Bang, and if time can emerge, it can also disappear - that's just the reverse effect," he says.

Time is running out - literally, says scientist


Are we missing a dimension of time?

Itzhak Bars - "current interests include mainly String Field Theory (SFT), and Two-Time Physics (2T-Physics), . . . " - http://physics1.usc.edu/~bars/research.html#2T

 

[Coin]

I am super confused by this article. What is it the Lancaster group actually did?

They say that the He3 superfluid resembles the large-scale structure of the universe. Did they prove this? Did they even try to prove it? Or did they just go "hey, it looks similar?"

When they say the He3 "form structures that... are similar [to] those seen in the cosmos." Does "the cosmos" mean the observable universe on a cosmological scale? Or do they mean the unobservable 11d "braneworld"?

When they say that the He3 can be used to test string theory. Do they mean that string theory predicts behaviors of superfluids, and this can be tested by observing the He3 superfluid? Or are they just saying, we have string theories of the cosmos, the cosmos is hard to observe, so instead let's just observe some He3 and assume the universe would have done the same thing?

Apparently the specific findings of the Lancaster group can be found in http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys815.html, but I don't have access to Nature's website so I don't know what it says...

 

[marcus]

Apparently the specific findings of the Lancaster group can be found in http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys815.html, but I don't have access to Nature's website so I don't know what it says...

Coin, Peter has links, several of which are free
for instance this article in Naturenews is free:
http://intl.emboj.org/news/2007/071221/full/news.2007.399.html[/URL]
It is by staff writer Geoff Brumfiel who used to write for New Scientist.
Peter says it is comparatively sensible (relative to the other stuff that came out) and it seems to have some detail,
now I see you have been at NEW too so none of this is news to you. Maybe somebody else can use the info.

I checked several on the Lancaster lowtemperature group, that authored, and they had not published very much---typically one, two, three papers on arxiv, not necessarily peer-review print. They wrote a paper about turbulence in cold He3 in 2006 which may have much the same sort of stuff, but just not hyped as a metaphor for the universe. So it didn't get the same attention.
I get the impression that hype about connection to string theory has become a cheap way to get attention---because nowadays it's not hard find a string theorist who will grab on and go with it: amplifying your work.

 

[elivil]

In fact, I think, their point is regarding quantum vortices in superfluids as topological defects of the same origin as such cosmic topological defects as cosmic strings or domain walls.

 

[Kny]

Update

Hi,

Just wanted to make this thread up2date. I'm part of a group at the Technical University of Denmark working in the same area, only using superconductors and their macroscopic quantum coherence rather than that of superfluids (theoretically, there is very little difference in the way one approaches one compared to the other).

Our work is part of a now closing ESF project called Coslab, in which it is attempted to recreate as many features of the early universe in a lab setting. For the experiment at hand, what is being considered is the rapid phase transitions just after the big bang as the universe cooled down. According to the Standard Model and string theory, all the fundamental forces were created by a series of symmetry breaking events (probably without gravity, as it is rather special, but I'm not sure as I am an experimentalist). The usual comparison is that of a ball on top of a very slippery symmetrical hill (think mexican hat) - it could stay there forever, it is just extremely unlikely. At some point it falls to some side, and ends up in the valley below. By doing this, it has effectively broken the symmetry of the system.

The idea of these experiments is to have a system, that you can cool rapidly (quench) through some phase transition temperature, and then look at how the resulting system is composed of smaller parts. The detected entities are called topological defects. We are trying to see if the domains of superconductivity expands only limited by the speed of information (light in the medium), or if some other effect is dragging it back. This goes back to a theory by T.W.H. Kibble (1976, 1980) and W.H. Zurek(1996), where the last paper is more or less the father of the idea of using solid-state systems to simulate cosmological phase transitions.

Please give the APS Focus article written on the background of one of our articles a glance, as the APS writer does a very nice job of making it approachable for people outside the field:
http://focus.aps.org/story/v17/st18