<tt>p</tt> † <tt>q</tt> : a tool for prototyping many-body methods for quantum chemistry
Nicholas C. Rubin, A. Eugene DePrince
Abstract
p†q is a C++ accelerated Python library designed to generate equations for many-body quantum chemistry methods and to realise proof-of-concept implementations of these equations for rapid prototyping. Central to this library is a simple interface to define strings of second-quantised creation and annihilation operators and to bring these strings to normal order with respect to either the true vacuum state or the Fermi vacuum. Tensor contractions over fully-contracted strings can then be evaluated using standard Python functions (e.g. NumPy's einsum). Given one- and two-electron integrals, these features allow for the rapid implementation and assessment of a wide array of many-body quantum chemistry methods.