Renormalization of QED near Decoupling Temperature

TL;DR

This paper investigates the renormalization of QED near decoupling temperatures, demonstrating the convergence of the perturbative series and how temperature changes affect the renormalization constants and electron self-mass.

Contribution

It provides a detailed analysis of temperature-dependent renormalization constants in QED near decoupling temperatures, highlighting differences during heating and cooling processes.

Findings

Perturbative series in QED converges below decoupling temperature.

Renormalization constants differ during heating and cooling.

Electron self-mass correction varies with temperature and background fermion density.

Abstract

We study the effective parameters of QED near decoupling temperatures and show that the QED perturbative series is convergent, at temperatures below the decoupling temperature. The renormalization constant of QED acquires different values if a system cools down from a hotter system to the electron mass temperature or heats up from a cooler system to the same temperature. At T = m, the first order contribution to the electron selfmass, {\delta}m/m is 0.0076 for a heating system and 0.0115 for a cooling system and the difference between two values is equal to 1/3 of the low temperature value and 1/2 of the high temperature value around T~m. This difference is a measure of hot fermion background at high temperatures. With the increase in release of more fermions at hotter temperatures, the fermion background contribution dominates and weak interactions have to be incorporated to understand the background effects.