Properties of compact objects in quadratic non-metricity gravity

TL;DR

This paper explores the properties of compact objects within quadratic non-metricity gravity, demonstrating that stable models align with observations and can exceed traditional density limits, with sound speeds remaining physically plausible.

Contribution

It introduces solutions for compact objects in quadratic non-metricity gravity, showing they can surpass nuclear saturation densities while remaining consistent with observational data.

Findings

Stable models match astronomical data

Core and surface densities can exceed nuclear saturation

Radial sound speed stays below conformal bound

Abstract

Astrophysical compact objects are studied in the context of quadratic non-metricity gravity. The solutions to the gravitational field equations, which include fluid components, are analyzed to investigate the density and pressure properties of radio pulsars. It is explicitly demonstrated that the theoretically stable models are consistent with astronomical data, due to the geometric features of the quadratic component. Furthermore, it is shown that, in contrast to the compactness limits of black holes in general relativity, the core density can significantly exceed the density at which nuclear saturation occurs, and the surface density can also surpass the value of nuclear saturation. Additionally, it is found that the radial sound speed remains below the conformal upper bound for sound velocity established by perturbative quantum chromodynamics.