Approximate Global Minimizers to Pairwise Interaction Problems via Convex Relaxation

We present a new approach for computing approximate global minimizers to a large class of nonlocal pairwise interaction problems defined over probability distributions. The approach predicts candidate global minimizers, with a recovery guarantee, that are sometimes exact, and often within a few percent of the optimum energy (under appropriate normalization of the energy). The procedure relies on a convex relaxation of the pairwise energy that exploits translational symmetry, followed by a recovery procedure that minimizes a relative entropy. Numerical discretizations of the convex relaxation yield a linear programming problem over convex cones that can be solved using well-known methods. One advantage of the approach is that it provides sufficient conditions for global minimizers to a nonconvex quadratic variational problem, in the form of a linear, convex, optimization problem for the autocorrelation of the probability density. We demonstrate the approach in a periodic domain for examples arising from mo...