QED Plasma at High Temperature

TL;DR

This paper investigates the properties of a relativistic QED plasma in the early universe around nucleosynthesis, focusing on temperature-dependent parameters like the coupling constant, Debye length, and plasma frequency.

Contribution

It applies QED renormalization to compute effective plasma parameters in the early universe, revealing how electromagnetic properties evolve with temperature.

Findings

QED coupling constant varies with temperature due to radiative corrections.

Debye length and plasma frequency depend on the universe's temperature.

Electromagnetic radiation slows down and becomes trapped in the plasma.

Abstract

We demonstrate that the early universe behaved as a relativistic QED (Quantum Electrodynamics) plasma around the nucleosynthesis time while the temperature of the universe was below the neutrino decoupling temperature in the early universe. QED coupling constant becomes a temperature dependent parameter due to the radiative corrections to vacuum polarization in the early universe at nucleosynthesis temperature. Renormalization scheme of QED is used to calculate the effective parameters of relativistic plasma in the early universe. Renormalization constants of QED serve as effective parameters of the theory and are used to determine the behavior of matter. We explicitly compute the parameters of QED plasma such as Debye length and the plasma frequency as a function of temperature. Light is slowed down and trapped due to bending in such a medium and the frequency of electromagnetic radiation becomes a function of temperature as well.