A model of phase fluctuations in a lattice d-wave superconductor:   application to the Cooper pair charge-density-wave in underdoped cuprates
  We introduce and study an XY-type model of thermal and quantum phase fluctuations in a two-dimensional correlated lattice d-wave superconductor based on the QED3 effective theory of high temperature superconductors. General features of and selected results obtained within this model were reported earlier in an abbreviated format (Z. Tesanovic, cond-mat/0405235). The model is geared toward describing not only the long distance but also the intermediate lengthscale physics of underdoped cuprates. In particular, we elucidate the dynamical origin and investigate specific features of the Cooper pair charge-density-wave (CPCDW), which we argue is the state behind the periodic charge density modulation discovered in recent STM experiments. We illustrate how Mott-Hubbard correlations near half-filling suppress superfluid density and favor an incompressible state which breaks translational symmetry of the atomic lattice. We show how the formation of the CPCDW in such a strongly quantum fluctuating superconductor can be understood as an Abrikosov-Hofstadter problem in a type-II dual superconductor, with the role of the dual magnetic field played by the electron density. The resulting Abrikosov lattice of dual vortices translates into the periodic modulation of the Bogoliubov-deGennes gap function and the electronic density. We compute detailed signatures of various Abrikosov-Hofstadter dual vortex arrays in the single-particle local tunneling density of states. A 4x4 checkerboard-type modulation pattern naturally arises as an energetically favored ground state at and near the x = 1/8 doping and produces good agreement with experimental observations. 
Ashot Melikyan and Zlatko Tesanovic