Speaker
Description
The presentation is based on 1, where we study the unhindered gravitational collapse of a massless scalar field—one of the fundamental matter fields determined by a Lagrangian formulation—in a spherically symmetric spacetime, working in a frame-independent and ansatz-independent formalism.
We identify a single dimensionless parameter that determines the end-state, which can be one of the following two: a singularity or dispersal. This same dimensionless parameter also decides the visibility of the end-state singularity, which is either a locally naked null singularity or a black hole. We also show that the null naked singularity is the critical case between the black hole and dispersal cases. Hence, in the associated phase space of this parameter, the critical solution is an attractor. We show the causal structures and the visibilities of the end-states of this collapse through their corresponding Penrose diagrams.
Due to the covariant formulation of this investigation and the critical parameter being dimensionless, the obtained results are independent of length scales and hold for all systems with the same underlying symmetric structures. This provides an analytic formulation of universality and critical behaviour in massless scalar field collapse, in agreement with earlier numerical studies.
| Other topic / keywords: | Gravitational collapse, critical phenomena, universality, mass-less scalar field dynamics. |
|---|