Calculating and resumming the classical virial expansion using automated algebra

Abstract

Using schematic model potentials, we calculate exactly the virial coefficients of a classical gas up to sixth order and use them to assess the convergence properties of the virial expansion of basic thermodynamic quantities such as pressure, density, and compressibility. At sufficiently strong couplings, as expected, the virial expansion fails to converge. However, at least for the interactions and parameter ranges we explored, we find that Pad\'e-Borel resummation methods are extremely effective in improving the convergence of the expansion.