Constant-roll and primordial black holes in f(Q,T) gravity

TL;DR

This paper explores how constant-roll inflation within $f(Q,T)$ gravity influences primordial black hole evolution, analyzing inflationary parameters and black hole mass dynamics with compatibility to observational data.

Contribution

It introduces an alternative method linking slow-roll and constant-roll parameters in $f(Q,T)$ gravity and studies primordial black hole evolution considering accretion and evaporation effects.

Findings

Spectral index and tensor-to-scalar ratio match Planck data for various $eta$ values.

Derived analytic estimates for primordial black hole masses in $f(Q,T)$ gravity.

Demonstrated the impact of modified gravity on black hole mass evolution.

Abstract

In this study, we investigate the consequence of the constant-roll condition and examine the role of $f(Q,T)$ gravity in the cosmological inflation process. We analyze the inflationary scenario by calculating modified Friedmann equations, and giving an alternative technique that enables relating modified slow-roll parameters to the constant roll parameter $\beta $. Considering both chaotic and hilltop models, we calculate the spectral index and the tensor-to-scalar ratio and compare their compatibility with Planck's data for different choices of the constant roll parameter $\beta $. We examine the evolution of primordial black holes in our chosen modified gravity model taking into account the accretion process and the evaporation due to Hawking radiation. We compute the evaporation and accretion masses rate and provide an analytic estimation of the primordial black holes masse and of the radiation in the $f(Q,T)$ gravity model.