Closed-form solutions for the highly anisotropic antiferromagnetic chain

We obtain the spectrum and derive closed-form solutions for the stationary states of the one-dimensional antiferromagnetic Heisenberg Hamiltonian in the quasi-Ising asymptotic limit. Comparison with exact numerical results for the ground state shows, however, good accuracy in a wide range of the anisotropy parameter. Since our solutions are simple and in closed analytical form a deep insight in the dynamics of linear antiferromagnets is obtained. The structure of the ground state presents similarities with the liquid-type disordered state proposed by Anderson. (author). 6 refs, 1 fig