These are some links to some articles related to my talk at KITP:
``Cuprates: Superconductivity near the nodes, Mottness at the antinodes'' Wed,Aug,29 12:00

- For a while now, I've been involved (together w/ Gabi Kotliar) in a collaboration w/ the Raman scattering group of Alain Sacuto at ESPCI and Paris-7. In a Nature Physics paper published in July 2006 (ArXiv link here) we proposed that the superconducting state of underdoped cuprates is actually characterized by two energy scales. The lowest of these two scales is associated with nodal physics and turns out to have the same dependence as Tc as a function of doping level. There is evidence that it is this lowest energy scale which is in fact associated with superconductivity and should be associated w/ the superconducting gap of cuprates.
- For earlier work related to our proposal, see the papers by G.Deutscher, and by J.Mesot et al. and Borisenko et al. quoted in our article.
- Several other experiments have addressed this issue since then, see e.g the recent photoemission experiments by Tanaka et al. (Science, 2006) and by Kondo et al. (PRL, 2007) and there seems to be growing evidence. See also the recent review posted by Hufner et al. on the ArXiv.
The phenomenon of momentum-space differentiation, with nodal and antinodal directions behaving in very different manners, poses a true challenge to theorists. Recently, I have been involved in cluster-DMFT studies wich reveal this phenomenon and support the two-gap picture in the superconducting state, see: M.Civelli et al. In another recent preprint, we have been trying to forge some low-energy tools (generalized versions of slave bosons) which can help in making progress on this issue by accouting for the momentum-dependence of the quasiparticle weight.