Non-singular quantum-inspired gravitational collapse

TL;DR

This paper explores quantum gravity-inspired modifications to gravitational collapse, showing that such effects can prevent singularity formation and eliminate event horizons, leading to potentially observable radiation from collapsing objects.

Contribution

It introduces an effective density approach based on quantum gravity that avoids singularities and alters the classical collapse outcome.

Findings

No formation of event horizons in the quantum-inspired collapse model.

Collapse results in a bounce and radiation emission instead of a black hole.

Apparent horizons form and disappear dynamically depending on density and quantum effects.

Abstract

We consider general relativistic homogeneous gravitational collapses for dust and radiation. We show that replacing the density profile with an effective density justified by some quantum gravity framework leads to the avoidance of the final singularity. The effective density acts on the collapsing cloud by introducing an isotropic pressure, which is negligible at the beginning of the collapse and becomes negative and dominant in the strong field regime. Event horizons never form and therefore the outcome of the collapse is not a black hole, in the sense that there are no regions causally disconnected from future null infinity. Apparent horizons form when the mass of the object exceeds a critical value, disappear when the matter density approaches an upper bound and gravity becomes very weak (asymptotic freedom regime), form again after the bounce as a consequence of the decrease in the matter density, and eventually disappear when the density becomes too low and the matter is radiated away. The possibility of detecting radiation coming from the high density region of a collapsing astrophysical object in which classically there would be the creation of a singularity could open a new window to experimentally test theories of quantum gravity.