Exact Solution of Ground State for Uniformly Distributed RVB in One-Dimensional Spin-1/2 Heisenberg Systems with Frustration

Abstract

The properties of the ground state in chain-like systems, including the competition between ferromagnetic and antiferromagnetic exchange interactions, are discussed. It is, in particular, pointed out that the characteristic singlet state expressed by the combinations of RVB distributed uniformly to spin lattice points is given as the exact solution on some condition of the competition. Besides analytical discussion, the numerical calculation for the spin number N ≦16 is also made so as to make clear the behavior of a multiple degeneracy for the ground state and of low-lying excitation levels.