Quantum effects on virial coefficients: A numerical approach using centroids

We develop a numerical methodology to calculate quantum corrected virial coefficients using the centroid approximation of the exact path-integral expression. This approach naturally takes into account any form of the many-body non-additive interaction potentials, and – in the case of helium – is shown to have an accuracy better than 1% for temperatures larger than 100 K. We apply it to the ab initio calculation of the fourth virial coefficient of 4He, using state-of-the-art pair and three-body potentials. Our results are an improvement with respect to the classical calculation and almost agree within mutual uncertainty with the latest experimental data.