If helium is 'superfluid' at low temperatures

Re: superfluid/superviscous

Sounds clever, regard with suspicion...

 

Re: superfluid/superviscous

What would be the properties of a superviscous amorphos soild?

 

Re: superfluid/superviscous

Superfluidity is a quantum effect, where the glass transition is a classical effect, as far as I know.

 

Re: superfluid/superviscous

I am not sure why you think superinsulators have anything to do with this; they are essentially just grainy films where the charging energy of single grains are larger than the availalble thermal energy which means that the charge carriers "freeze out" at low temperatures (it is a bit more complictated than this, since there are some collective effects involved, but that is the essence of it); it is essentially a classical effect and there is no macroscopic coherence involved.

And yes, I do know that the Novosibirsk people like to say that that the conductor-superinsulator transition is analogous to the normal-superconductivity transition; but there are significant differences.

 

Re: superfluid/superviscous

Well, the Wikipedia article isn't very accurate in this case. It is true that the effect is observed when the grains are superconducting; but this does not change what I wrote above. If you want you can think of the system as a network of Cooper pair boxes (which is why you need the grains to be superconducting); but the interaction between these are -as far as I know- still just classical (there is a synchronization of the phase BETWEEN the grains; but there is still no GLOBAL phase; the system is not described by a "single wavefunction").
Note that the idea is far from new and as far as I remember there is even a brief discussion in Tinkham.

I am familiar with the article, and I've also attended a few talks by among others Baturina so hopefully I have some idea about how this work (at one point we were considering using superinsulators in one of our own projects).

 

Re: superfluid/superviscous

No offense, but your post makes no sense at all.
If you don't believe superfluidity involved "real movement" you should check out some of the videos of superfluids on Youtube or -even better- find a nearby university that holds public demonstrations where effects like superfluid helium "creeping out" of a container (via the Rollin film) are shown. I used to supervise a demonstration of superfluidity to undergraduate students, it is quite a nice demonstration and most of the effects are quite easy to see.

Note also that there are quite a few engineering applications where this is used; one way to separate He-3 and superfluid He-4 is to use a "superleak"; basically a barriers with holes so small that only superfluids can pass through (and once you heat up the He-4 it becomes a normal liquid again). This is used in e.g. dilution refrigerators.

Also, you shouldn't take the London theory too seriously. It is a phenomenological theory which is often useful but it doesn't even try to describe what goes on at the microscopic level, for that you need more sophisticated theories based on QM.