TY  - JOUR
AU  - Maso-Ferrando, A.
AU  - Sanchis-Gual, N.
AU  - Font, J. A.
AU  - Olmo, G. J.
PY  - 2023
DA  - 2023//
TI  - Birth of baby universes from gravitational collapse in a modified-gravity scenario
T2  - J. Cosmol. Astropart. Phys.
JO  - Journal of Cosmology and Astroparticle Physics
SP  - 028
EP  - 19pp
VL  - 06
IS  - 6
PB  - IOP Publishing Ltd
KW  - modified gravity
KW  - Wormholes
AB  - We consider equilibrium models of spherical boson stars in Palatini f (R) = R + CR2 gravity and study their collapse when perturbed. The Einstein-Klein-Gordon system is solved using a recently established correspondence in an Einstein frame representation. We find that, in that frame, the endpoint is a nonrotating black hole surrounded by a quasi -stationary cloud of scalar field. However, the dynamics in the f (R) frame is dramatically different. The innermost region of the collapsing object exhibits the formation of a finite -size, exponentially-expanding baby universe connected with the outer (parent) universe via a minimal area surface (a throat or umbilical cord). Our simulations indicate that this surface is at all times hidden inside a horizon, causally disconnecting the baby universe from observers above the horizon. The implications of our findings in other areas of gravitational physics are also discussed.
SN  - 1475-7516
UR  - https://arxiv.org/abs/2304.12018
UR  - https://doi.org/10.1088/1475-7516/2023/06/028
DO  - 10.1088/1475-7516/2023/06/028
LA  - English
N1  - WOS:001025474200010
ID  - Maso-Ferrando_etal2023
ER  -