Path Integral Ground State with a Fourth-Order Propagator: Application to Condensed Helium

TL;DR

This paper improves the Path Integral Ground State method for condensed Helium by implementing a fourth-order propagator, demonstrating comparable or superior accuracy to existing quantum Monte Carlo techniques.

Contribution

The paper introduces a fourth-order short-time propagator for PIGS, enhancing its accuracy and efficiency in calculating ground state properties of condensed Helium.

Findings

Fourth-order propagator performs comparably to pair product approximation.

Far superior to primitive approximation in accuracy.

PIGS results for Helium's equation of state are competitive with other QMC methods.

Abstract

Ground state properties of condensed Helium are calculated using the Path Integral Ground State (PIGS) method. A fourth-order approximation is used as short (imaginary) time propagator. We compare our results with those obtained with other Quantum Monte Carlo techniques and different propagators. For this particular application, we find that the fourth-order propagator performs comparably to the pair product approximation, and is far superior to the primitive approximation. Results obtained for the equation of state of condensed Helium show that PIGS compares favorably to other QMC methods traditionally utilized for this type of calculation.