On the Vlasov equation for Schwinger pair production in a time-dependent electric field

Schwinger pair creation in a purely time-dependent electric field can be described through a quantum Vlasov equation describing the time evolution of the single-particle momentum distribution function. This equation exists in two versions, both of which can be derived by a Bogoliubov transformation, but whose equivalence is not obvious. For the spinless case, we show here that the difference between these two evolution equations corresponds to the one between the "in-out" and "in-in" formalisms. We give a simple relation between the asymptotic distribution functions generated by the two Vlasov equations. As examples we discuss the Sauter and single-soliton field cases.Comment: 15 pages, 2 figures, final published version (substantially extended

New relations between spinor and scalar one-loop effective Lagrangians in constant background fields

Simple new relations are presented between the one-loop effective Lagrangians of spinor and scalar particles in constant curvature background fields, both electromagentic and gravitational. These relations go beyond the well-known cases for self-dual background fields

Spinor and scalar effective actions in gauge-theories

In this dissertation, I investigate the effective action in gauge theories. I present new relations between the spinor and scalar one-loop effective action in constant electromagnetic background fields. I apply similar techniques to show a new correspondence between the spinor and scalar one-loop effective action in curved spacetime. Functional determinants are related to the effective action. I study how some recently developed techniques for calculating functional determinants on radially symmetric backgrounds may be applied to different problems in spinor gauge theories. There are only a few known closed-form results for the effective action at the two-loop level. I present a closed-form for the weak-field expansion coefficients of the two-loop Euler-Heisenberg effective action on a magnetic or electric field.