The Superfluid Density in the D-density-wave Scenario
  Recently Chakravarty, Laughlin, Morr and Nayak made an interesting proposal that the cuprate superconductors possess a hidden ``d-density wave'' order. We study the implication of this proposal for the superfluid density \rho_s. We find that it predicts a temperature gradient |d\rho_s/dT|_{T=0} that is strongly doping dependent near the critical doping (\approx 5%) at which the superconducting transition temperature vanishes. 
Qiang-Hua Wang, Jung Hoon Han, and Dung-Hai Lee