Gravitational Particle Creation in a Stiff Matter Dominated Universe

TL;DR

This paper investigates gravitational particle creation in a stiff matter universe, showing that particle production depends heavily on scalar mass and expansion rate, with implications for early universe cosmology.

Contribution

It provides a detailed calculation of scalar particle creation in a stiff matter universe using quantum field theory in curved spacetime, highlighting the dependence on mass and expansion.

Findings

Particle creation is most effective for massive scalars and rapid expansion.

An upper bound for the temperature of secondary particles is derived.

Results have implications for early universe thermal history.

Abstract

A scenario for gravitational particle creation in a stiff matter dominated flat Friedmann-Robertson-Walker universe is presented. The primary creation of scalar particles is calculated using quantum field theory in curved spacetime and it is found to be strongly dependent on the scalar mass and the expansion parameter of the universe. The particle creation is most effective for a very massive scalar field and large expansion parameter. We apply the results to cosmology and calculate an upper bound for the equilibrium temperature of the secondary particles created by the scalar field decay.