Baryon-photon interactions in Resummed Kinetic Field Theory

TL;DR

This paper extends Kinetic Field Theory to include baryon-photon interactions, modeling pressure effects to qualitatively reproduce baryon-acoustic oscillations in the cosmological power spectrum.

Contribution

It introduces a modified mesoscopic particle model within KFT that incorporates baryon-photon interactions and pressure effects.

Findings

Model qualitatively reproduces baryon-acoustic oscillations

Incorporates photon interactions into mesoscopic particle description

Provides a framework for baryon-photon fluid dynamics in cosmology

Abstract

We explore how interactions between baryons and photons can be incorporated into Kinetic Field Theory (KFT), a description of cosmic structure formation based on classical Hamiltonian particle dynamics. In KFT, baryons are described as effective mesoscopic particles which represent fluid elements governed by the hydrodynamic equations. In this paper, we modify the mesoscopic particle model to include pressure effects exerted on baryonic matter through interactions with photons. As a proof of concept, we use this extended mesoscopic model to describe the tightly coupled baryon-photon fluid between matter-radiation equality and recombination. We show that this model can qualitatively reproduce the formation of baryon-acoustic oscillations in the cosmological power spectrum.