Phase diagram of the one-dimensional t-J model from variational theory

We study a class of variational wave functions for strongly interacting one-dimensional lattice fermions in which correlations among the particles are specified by a single variational parameter. We find that the wave functions describe the ground-state properties of the one-dimensional t-J model remarkably well over the entire phase diagram in which interaction strength and density are varied. Specifically the wave function describes a Tomonaga-Luttinger liquid at low J/t, a phase-separated state at large J/t, and a stable state with infinite compressibility between these phases at low densities.