Closing summary

After the thanks for Doreen and the bloggers.

Paul Canfield stands up to make a point. In general there seem to be two classes of material.
(1) The old style: MgB2, RNi2B2C, Nb3Ge
They are relatively easy to make and doing stuff to them makes them worse superconductors. They are ordered and reveal their superconducting state easily.
(2) New style: FeAs CuO
These are harder to make and generally need to be doped from a parent (host state) to make them superconductors to remove some other state.
Paul says we know so little that it does not matter what the rational is, as long as we are looking we will find stuff. But, what would be useful to the experimentalists ("animals invited to this paradise") from the theorists is what sort of host materials should we be looking at to reduce the size of the phase space. The hosts will probably be non superconducting.
Laura Greene: well Philip^2 and Si have pointed to Mott insulators as being a good starting point. Also, theorists don't always help because they don't understand stuff that we do about the compounds and so have a simplistic view of the changes that really take place on doping.

Piers Coleman: this is just the start of a better collaboration between the materials and the theorists. It was great to have Juri. But here is an issue: theorists live mainly in momentum space but the chemistry lies in real space. Here perhaps heavy fermions have something to offer.

Andrey Chubukov: Plot Tc against Hubbard U/W then "obviously Tc goes up from the small U/W limit, it must also go down at large U/W. What seems surprising is that Tc is rather flat in the intermediate region with Tc ~ 0.02E_F (Piers says it is not true in heavy fermions). This means Tc ~200K max.

And at this point your blogger must leave for his flight...so over to Sam.

Rick Green: Question to Andrey: what about pressure, which seems to increase superconductivity?
Andrey: Well, the top won't be perfectly flat, and this is a very schematic picture.

Andrey: This was about Tc in the absence of competing orders. Of course, when there is competing order the picture changes. But just to emphasize again, the numbers are quite interesting - that Tc always comes out about 2% of the Fermi energy.

Question: What about dimensionality? Should we stick to 2D systems, or maybe try and move elsewhere?
Andrey: In fact, this picture is quite general in the generic shape; but the more dimensions, the more factors of 2pi and the more small pieces of BZ you have to worry about, so the numbers come out smaller.

Piers: What about condensation entropy? Never seen it go about about 1/3 log 2. That's another way of thinking of these limits.

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Piers: Now that we've finished scientific questions, what about organization issues. Should we have less talks (seems to be a general consensus that the number of talks is actually quite good). What about more people - many more people could fit in this lecture theatre.
Laura Greene: I'd like to see many more young people.
Piers + Andrey: A lot of this is a question of money - we have to look into getting more funding.
Andriy: What about holding it in the Adriatico lecture hall, rather than this one in the main building? Seems to be general consensus that main building is better.

Well, that's the end!!! Two weeks have gone by very quickly. Ciao tutti.