Variational Approach to Correlations in Polymers

A deterministic algorithm for calculating polymer properties is presented. It is based on a variational approach where the bond and Coulomb potentials are approximated by a quadratic trial energy. The parameters, which describe average atom positions and Gaussian uctuations, are the solutions of matrix equations. By a judicious choice of parameter representations and the use of incremental matrix inversion, an eecient iterative algorithm is constructed that is several orders of magnitude faster than MC methods. The method is explored numerically at realistic temperatures with results that agree within 5% with those of MC calculations.