Electromagnetic plasma waves in Big Bounce and Big Crunch cosmologies

TL;DR

This paper analyzes electromagnetic wave behavior in electron-positron plasma within Big Bounce and Big Crunch cosmologies, revealing Mathieu equation descriptions and potential wave amplification effects due to the cosmological constant.

Contribution

It provides exact solutions for electromagnetic waves in these cosmologies, highlighting the mathematical form and physical implications of wave amplification and collapse.

Findings

Electromagnetic waves follow Mathieu equations in both cosmologies.

Wave amplification possible in Big Bounce cosmology due to the cosmological constant.

Waves exhibit growth or collapse patterns reflecting universe dynamics.

Abstract

We study the exact dynamics of electromagnetic waves in cold electron-positron plasma in the simplest background of Big Bounce and Big Crunch cosmologies. We show that these waves are described by a Mathieu equation in a Big Bounce cosmology, which opens the possibility of electromagnetic wave amplification due to the cosmological constant in this Universe. On the contrary, in a Big Crunch cosmology, electromagnetic plasma waves are described by a modified Mathieu equation. In both cases, the features (grow/collapse) of the Universes imprint similar characteristics in the temporal evolution of these waves.