Key points are not available for this paper at this time.
The Green's function G (k, ) is calculated for a hole in a Hubbard antiferromagnet by a new nonperturbative, variational method for an infinite square lattice. The quasiparticle and excited-state wave functions show that the substantial structure in the ``incoherent'' spectrum is related to string states for large U. The strength of the quasiparticle pole and the anisotropic effective mass are obtained as a function of (U/t). The quasiparticle lifetime is infinite for most k.
S. A. Trugman (Mon,) studied this question.