Cosimo Bambi, Daniele Malafarina, Leonardo Modesto
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. For sufficiently small sources, the horizon never forms. For larger objects, the horizon forms, it disappears when the matter density approaches a critical value and gravity becomes very weak (asymptotic freedom regime), it forms again after the bounce as a consequence of the decrease in the matter density, and it eventually disappears when the density becomes too low and the matter is radiated away. In both cases, the bounce stage regulated by quantum gravity effects turns out to be visible to distant observers. 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.
View original:
http://arxiv.org/abs/1305.4790
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