DYNAMICS OF ONE HOLE IN THE T-J MODEL

We calculated the spectral function of a hole in the t-J model using a numerical method on a 4×4 lattice. A sharp quasiparticle peak is observed with an energy that is well approximated by E=-3.17+2.83J (for 0.1J1.0, t=1) with =0.730.02. This result suggests that the picture of a hole attached to the origin by a string may be valid in the Heisenberg model. The rest of the spectrum is not completely incoherent but it has a nontrivial structure, stemming from the excited states of the string. The bandwidth of the quasiparticle is discussed. Results for the Ising model are also presented. © 1990 The American Physical Society.