Gravitational Dark Matter from Minimal Preheating

TL;DR

This paper investigates gravitational dark matter production during minimal preheating caused by inflaton self-resonance, predicting relic abundance based on a single inflation parameter and using lattice simulations to analyze non-perturbative effects.

Contribution

It provides a robust prediction of gravitational dark matter relic abundance from minimal preheating, highlighting the dependence on the inflation potential parameter n and including non-perturbative lattice analysis.

Findings

Relic abundance predictions for dark matter masses around 10^14 GeV.

Dominance of inflaton condensate contribution for n=4,6.

Absence of condensate contribution for n=2.

Abstract

Following our previous work, we continue to explore gravitational dark matter production during the minimal preheating caused by inflaton self-resonance. In this situation there is only one dimensionless index parameter $n$ characterizing the inflation potential after the end of inflation, which leads to a robust prediction on the gravitational dark matter relic abundance. Using lattice method to handle the non-perturbative evolutions of relevant quantities during the inflaton self-resonance, we derive the gravitational dark matter relic abundance arising from both the inflaton condensate and fluctuation annihilation. While being absent for $n=2$, the former one can instead dominate over the later one for $n=4,6$. Our results show that gravitational dark matter mass of $1.04~(2.66)\times 10^{14}$ GeV accommodates the observed value of dark matter relic abundance for $n=4$ (6).