We present an algorithm to systematically improve wavefunctions in the variational Monte Carlo method for the t-J model. The ground-state wavefunction is approximated by a linear combination of single-particle states with Gutzwiller projection. The single-particle states are successively generated according to the numerical path-integral renormalization group (PIRG) procedure. In the initial step, the present method reduces to the usual variational Monte Carlo method. As the number of single-particle states increases, the wavefunction converges to the ground-state wavefunction. Applying this method to the two-dimensional t-J model, we have confirmed that the wavefunction, which is composed of a small number of single-particle states, gives a good estimate of the ground-state energy. This algorithm does not suffer from the negative sign problem and can be applied to the models with strong correlations.
ASJC Scopus subject areas
- 化学 (全般)