Effective Action and Schwinger Pair Production in Scalar QED

Abstract

Some astrophysical objects are supposed to have very strong electromagnetic fields above a critical strength. Quantum vacuum fluctuations due to strong electromagnetic fields modify the Maxwell theory and particularly electric fields make the vacuum unstable against pair production of charged particles. By finding the effective action, we study the strong field effect, the vacuum polarization due to the real part of the effective action and the Schwinger pair production due to the imaginary part of the effective action in scalar quantum electrodynamics (QED).