QUANTUM SCATTERING FROM CLASSICAL FIELD-THEORY

We show that scattering amplitudes between initial wave packet states and certain coherent final states can be computed in a systematic weak coupling expansion about classical solutions satisfying initial-value conditions. The initial-value conditions are such as to make the solu tion of the classical field equations amenable to numerical methods. W e propose a practical procedure for computing classical solutions whic h contribute to high energy two-particle scattering amplitudes. We con sider in this regard the implications of a recent numerical simulation in classical SU(2) Yang-Mills theory for multiparticle scattering in quantum gauge theories and speculate on its generalization to electrow eak theory. We also generalize our results to the case of complex traj ectories and discuss the prospects for finding a solution to the resul ting complex boundary value problem, which would allow the application of our method to any wave packet to coherent state transition. Finall y, we discuss the relevance of these results to the issues of baryon n umber violation and multiparticle scattering at high energies.