Two-color phase-of-the-phase spectroscopy applied to nonperturbative electron-positron pair production in strong oscillating electric fields

TL;DR

This paper applies phase-of-the-phase spectroscopy to analyze electron-positron pair production in strong bichromatic electric fields, revealing characteristic asymmetric patterns and coherence effects in the momentum-resolved yields.

Contribution

It introduces phase-of-the-phase spectroscopy to the study of nonperturbative pair production, providing new insights into coherence effects in strong-field quantum electrodynamics.

Findings

Asymmetric checkerboard patterns in phase spectra

Differences in structures between electrons and positrons

Physical interpretation of phase-dependent coherence effects

Abstract

Production of electron-positron pairs from vacuum in strong bichromatic electric fields, oscillating in time with a fundamental frequency and its second harmonic, is studied. Strong-field processes occuring in such field configurations are generally known to be sensitive to the relative phase between the field modes. Phase-of-the-phase spectroscopy has recently been introduced in the context of strong-field photoionization as a systematic means to analyze these coherence effects. We apply this method to field-induced pair production by calculating the phase dependence of the momentum-resolved particle yields. We show that asymmetric checkerboard patterns arise in the phase-of-the-phase spectra, similarly to those found in strong-field photoionization. The physical origin of these characteristic structures, which differ between the created electron and positron, are discussed.