Crossover from d-wave to p-wave pairing in the t-t′ Hubbard model at zero temperature

We develop an algorithm which employs the projective quantum Monte Carlo method for solving the equations of the dynamical cluster approximation at zero temperature, and apply it for studying pair susceptibilities of the two-dimensional Hubbard-model with next-nearest neighbor hopping. In particular, we identify which pairing symmetry is dominant in the U-n parameter space (U: repulsive Coulomb interaction; n: electron density). We find that p(x+y)(-)(d(x)(2)-y(2-)) wave is dominant among triplet (singlet) pairings-at least for 0.3 < n < 0.8 and U <= 4t. The crossover between d(x)(2)-y(2-) wave and p(x+y)(-) wave occurs around n similar to 0.4.