Scalar field collapse in a conformally flat spacetime

Abstract

The collapse scenario of a scalar field along with a perfect fluid distribution is investigated for a conformally flat spacetime. The theorem for the integrability of an anharmonic oscillator has been utilized. For a pure power law potential of the form φ n+1 , it is found that a central singularity is formed which is covered by an apparent horizon for n > 0 and n < −3. Some numerical results have also been presented for a combination of two different powers of φ in the potential. *

Self similar collapse and the Raychaudhuri equation

“…With an exact solution, one can explicitly find whether there is a collapse or an expansion and whether the collapse, if there is any, results in a singularity. We have checked that in all such cases the conclusions are consistent with those obtained from the focusing condition (27) found out from the Raychaudhuri equation. One such nontrivial example is described in detail below.…”

Collapsing spherical star in Scalar-Einstein-Gauss-Bonnet gravity with a quadratic coupling

“…The theorem which inspires this method is self sufficient as was discussed by Euler [65]. The same has been proved in the context of a massive scalar field minimally coupled to gravity by Chakrabari and Banerjee [61], where the solutions found by virtue of this theorem indeed solve the Klein Gordon type evolution equation once they are put back in the equation. In the current context, the solutions are far more complicated to say the least, as is evident from the expression of the scalar field, as worked out in details in section V .…”

Scalar field collapse in Gauss–Bonnet gravity

“…(28), eqn. (29) and eqn. (30) completely specify the matching at the boundary of the collapsing scalar field with an exterior generalized Vaidya geometry.…”

“…Thus for a collapsing geometry where the curvature becomes very large near the final state of the collapse, the higher curvature terms are expected to play a crucial role. Motivated by this idea, the collapsing scenarios in the presence of F (R) gravity have been recently discussed by Goswami et al [28] and by Chakrabarti and Banerjee [29,30].…”