Alex Simpson

TL;DR: In this article, the authors investigate a particularly interesting regular black hole spacetime described by the line element, where the origin can be either spacelike, null, or timelike.

Abstract: We develop a number of novel ``black-bounce'' spacetimes. These are specific regular black holes where the area radius always remains nonzero, thereby leading to a ``throat'' that is either timelike (corresponding to a traversable wormhole), spacelike (corresponding to a ``bounce'' into a future universe), or null (corresponding to a ``one-way wormhole''). We first perform a general analysis of the regularity conditions for such a spacetime and then consider a number of specific examples. The examples are constructed using a mass function similar to that of Fan-Wang and fall into several particular cases, such as the original Simpson-Visser model, a Bardeen-type model, and other generalizations thereof. We analyze the regularity, energy conditions, and causal structure of these models. The main results are several new geometries, more complex than before, with two or more horizons, with the possibility of an extremal case. We derive a general theorem regarding static spacetime regularity and another general theorem regarding (non)satisfaction of the classical energy conditions.

TL;DR: In this paper, the authors considered a class of regular black holes with asymptotically de Sitter regions at their cores, and they showed that these models greatly simplify the physics in the deep core.

TL;DR: In this article, a non-static evolving version of the regular "black-bounce"/traversable wormhole geometry was considered, where the mass parameter m depends on the null time coordinate (a la Vaidya).

TL;DR: In this article, the authors consider the black-bounce-Reissner-Nordstrom (RBN) spacetimes and the black bounce-Kerr-Newman (BKN) Spacetimes, and verify the existence of a Killing tensor (and associated Carter-like constant) without the full Killing tower of principal tensor and Killing-Yano tensor.