Collapsing dust thin shells in Einstein–Gauss–Bonnet gravity

Abstract

We investigate gravitational collapse of a spherically symmetric thin shell in the Einstein–Gauss–Bonnet (EGB) gravity. Under the recently proposed 4D limit, we find that the collapsing shell will be bounced back at a small radius, without forming a singularity. This bouncing behavior is similar to those of a test particle and a homogeneous spherical dust star, in accordance with the expectation that the Gauss–Bonnet term will modify the small scale behavior of the Einstein gravity. We analyze the causal structure of the dynamic spacetime that represents the bouncing process, finding that the thin shell has an oscillation behavior on the Penrose diagram, which means that the thin shell results in a novel type of black hole with respect to observers outside the event horizon that the collapse forms. We also find that the weak cosmic censorship conjecture holds in this model. Further implications of such a regular gravitational collapse are discussed.

Einstein-Gauss-Bonnet dark matter halo: negative masses, rotation curves and the origin of dark matter effects

“…The Israel junction is also employed in works akin to string theory, such as spherical collapse or thin-shell wormhole studies. Furthermore, without losing generality, equation (15) agrees with the results from multiple studies, such as [85,86]. We assume that the observer is too far from the center, so we have approximately (1…”

Confinement and null-source collision in a particular 4-dimensional third-order Lovelock gravity

“…Surprisingly, against this trend, it has been proposed that in D = 4, there are physical contributions for both GB and higherorder Lovelock theories. It is argued that the action is problematic in the limit D → 4, but this handicap can be overcome with the proper scaling of the coupling parameter [6][7][8][9][10][11][12][13][14][15]. As a result of scaling the full equations become acceptable as long as they admit solutions in agreement with observations such as general relativistic and Newtonian limits.…”

Testing viable extensions of Einstein-Gauss-Bonnet gravity

“…Also scenarios with bouncing solutions have been proposed within GB gravities [31,39,40]. In addition, (E)GB gravities have drawn a lot of attention within strong-field regimes, since might provide a different and richer spectrum of solutions for compact objects than in GR [53][54][55][56], which consequently may lead to some astrophysical signs that would be used in the future to constrain gravitational theories and test departures from GR [57][58][59][60][61][62][63][64][65][66][67]. Some modified GB models of the late-time cosmological evolution have been tested with observational data.…”