Analytic extensions of Monte Carlo calculations

The term quasiclassical is defined to apply to a large class of fundamentally equivalent approximations currently used for reactions involving complex quantum mechanical systems. Their relation to the underlying quantum mechanical problem is clarified. Monte Carlo calculations play a central and paradigmatic role within this class. Analytic formulas for inclusive cross sections involving simple integrals over functions obtained through a Monte Carlo calculation are presented. These are of a completely obvious nature but apparently have not been previously presented. They should greatly increase the convergence rate and range of applicability of Monte Carlo calculations and of quasiclassical calculations is general. The method of derivation allows straightforward generalization to arbitrary final states.NUCLEAR REACTIONS Quasiclassical stochastic models as quantum mechanical approximations. Monte Carlo trajectories as integration grid maximizes information content utilization. Smooth cross sections also valid for infrequent final states. General perturbation theory.