Are Most Particles Gravitons?

TL;DR

This paper explores the possibility that the universe contains an enormous number of gravitons, potentially exceeding other particles by many orders of magnitude, depending on inflationary parameters.

Contribution

It proposes a theoretical estimate of the number of gravitons in the universe based on inflationary quantum fluctuations and compares it to other fundamental particles.

Findings

Number of gravitons could be around 10^{113} times the tensor-to-scalar ratio

Graviton count may vastly surpass baryons, electrons, photons, and neutrinos

Inflationary parameters influence the estimated graviton abundance

Abstract

The number of baryons in the observable universe is of the order of $10^{80}$, as is the number of electrons. The number of photons is about nine orders of magnitude greater, $10^{89}$, as is the estimated number of neutrinos. However, the number of gravitons could be more than twenty orders of magnitude larger yet, of the order of $10^{113} r$, where $r$ is the tensor-to-scalar ratio for quantum fluctuations produced by inflation, which could be as high as $0.1$.