Electron-positron vacuum instability in strong electric fields. Relativistic semiclassical approach

TL;DR

This paper investigates the instability of the electron-positron vacuum in strong electric fields, exploring phenomena like vacuum polarization, spontaneous positron production, and electron condensation using a relativistic semiclassical approach.

Contribution

It provides a comprehensive analysis of vacuum instability phenomena in strong fields, including new insights into electron condensation and the effects of finite-size nuclei.

Findings

Electron-positron vacuum becomes unstable at high Z values.

Spontaneous positron production occurs for nuclei with Z>Z_cr~170.

Electron condensation phenomena are identified in supercharged nuclei.

Abstract

Instability of electron-positron vacuum in strong electric fields is studied. First, falling to the Coulomb center is discussed at $Z>137/2$ for a spinless boson and at $Z>137$ for electron. Then, focus is concentrated on description of deep electron levels and spontaneous positron production in the field of a finite-size nucleus with the charge $Z>Z_{\rm cr}\simeq 170$. Next, these effects are studied in application to the low-energy heavy-ion collisions. Then, we consider phenomenon of "electron condensation" on levels of upper continuum crossed the boundary of the lower continuum $\epsilon =-m$ in the field of a supercharged nucleus with $Z\gg Z_{\rm cr}$. Finally, attention is focused on many-particle problems of polarization of the QED vacuum and electron condensation at ultra-short distances from a source of charge. We argue for a principal difference of cases, when the size of the source is larger than the pole size $r_{\rm pole}$, at which the dielectric permittivity of the vacuum reaches zero, and smaller $r_{\rm pole}$. Some arguments are presented in favor of the logical consistency of QED. All problems are considered within the same relativistic semiclassical approach.