One-hole spectral densities in the polarized t-J model

We study the dynamics of one hole in the polarized t-J model. The model describes the physics of holes in polarized antiferromagnetic systems and the one-particle excitations in strong-coupling superconductors as well. The spectral densities of a single hole are calculated numerically using exact diagonalization of small clusters with toroidal boundary conditions. The quasiparticle spectrum is analyzed in detail. We show that a coherent quasiparticle peak is well defined for J/t>0.2. The dispersion relation of the quasiparticle is obtained for different magnetizations. The results are used to discuss the characteristics of one-particle excitations in small-coherence-length superconductors