Control of the laser-induced vacuum decay by electronic phases

Abstract

We examine the laser-assisted electron-positron pair-creation process from the quantum vacuum in the presence of a binding potential with one optically active bound electron. If this core electron is initially prepared in a coherent superposition state of two resonant bound states, the electronic phase properties between both state excitations can be transferred to the positron during the pair-creation process. For example, the periodic Rabi population exchange between both electronic states modulates the temporal growth of the pair-creation probability and also leads to an Autler-Townes split positron energy spectra. Even more astonishing, for the case of different phases, for which the internal electronic dynamics (in the absence of pair creation) is identical, the positron's creation probability is different, suggesting that the vacuum decay process can ``sense'' the phase and not just the occupation number of the core electron. The field theoretical model of the laser assisted pair-creation process with subsequent electron capture can be mapped exactly onto two mutually independent (single-electron) ionization-like processes. This mathematical equivalency permits us to derive analytical solutions for the time evolution of the vacuum decay process under the rotating-wave approximation.