Proximity of the Superconducting Dome and the Quantum Critical Point in   the Two-Dimensional Hubbard Model
  We use the dynamical cluster approximation to understand the proximity of the superconducting dome to the quantum critical point in the two-dimensional Hubbard model. In a BCS formalism, $T_c$ may be enhanced through an increase in the d-wave pairing interaction ($V_d$) or the bare pairing susceptibility ($\chi_{0d}$). At optimal doping, where $V_d$ is revealed to be featureless, we find a power-law behavior of $\chi_{0d}(\omega=0)$, replacing the BCS log, and strongly enhanced $T_c$. We suggest experiments to verify our predictions. 
Shu-Xiang Yang, Herbert Fotso, Shi-Quan Su, Dimitrios Galanakis, Ehsan   Khatami, Jian-Huang She, Juana Moreno, Jan Zaanen, ...
cond-mat.supr-con cond-mat.str-el