Pair Production in Intense External Fields

We study pair production of fermions and bosons from a variety of classical, external fields: vector, scalar, and pseudoscalar. We give a general prescription for the pair production rate for arbitrarily time-varying (but spatially uniform) fields. We point out a formal connection between the problem of pair creation in an external field and supersymmetric quantum mechanics. Analytic expressions for the pair production rate, obtained using a uniform semi-classical approximation, are presented for several field configurations; numerical results are presented for various field configurations for which the uniform approximation is not applicable. We calculate the multiplicities of produced fermions and bosons, and demonstrate their relation to the symmetric functions. We also calculate the combinants of produced pairs, and discuss the role of combinants in analyzing data.