Local representation of N-body Coulomb energy with path integrals

We represent N-body Coulomb energy in a localized form to achieve massive parallelism. It is a well-known fact that Green's functions can be written as path integrals of field theory. Since two-body Coulomb potential is a Green's function of Poisson equations, it reduces to a path integral of free scalar field theory with three spatial dimensions. This means that N-body one also reduces to a path integral. We discretize real space with a cubic lattice and evaluate the obtained multiple integrals approximately with the Markov-chain Monte Carlo method.