Variational Study of the Spin-Gap Phase of the One-Dimensional t-J Model

Abstract

We propose a correlated spin-singlet-pairs wave function to describe the spin-gap phase of the one-dimensional $t-J$ model at low density. Adding a Jastrow factor with a variational parameter, $ν$, first introduced by Hellberg and Mele, is shown to correctly describe the long-range behavior expected for the Luther-Emery phase. Using the variational Monte Carlo method we establish a relation between $ν$ and the Luttinger exponent $K_ρ$, $K_ρ=\frac{1}{2ν}$.