Like its sister project, the QVEE, this project aims to calculate the coefficients of the virial expansion of an interacting gas. Here, the gas is assumed to be classical, i.e. there are no complications coming from quantum mechanics (such as non-commuting operators).
The CVEE automates the diagrammatic algebra required to evaluate the terms that make up the canonical partition functions that enter the virial coefficients at each order. Terms that are irrelevant are identified and discarded along the way, saving the required terms for numerical evaluation at the end. In cases where the so-called f-factors can be written as Gaussians (or sums of Gaussians), the integrals can be evaluated exactly, without resorting to numerical methods. Interestingly, this allows one to explore a wide range of physical situations, such as purely repulsive potentials, as well as potentials with attractive pockets.
This material is based upon work supported by the National Science Foundation under Grant No. PHY2013078.