Matt Visser

TL;DR: Projectable Hořava-Lifshitzim theory of gravity as mentioned in this paper is a renormalizable version of gravity which abandons local Lorentz invariance.

TL;DR: This work presents an "emergent" spacetime model, based on the "analogue gravity" program, by investigating a specific condensed-matter system and shows that this model is an example for Lorentz invariance violation due to ultraviolet physics.

TL;DR: In this paper, the authors consider the construction of spherically symmetric thin-shell traversable wormholes within the context of standard general relativity, and apply a dynamical analysis to the wormhole throat by considering linearized radial perturbations around static solutions.

TL;DR: The Kiselev black hole spacetime model is an extremely popular toy model, with over 200 direct and indirect citations as of 2019 as mentioned in this paper. But despite repeated assertions to the contrary, this is not a perfect fluid spacetime, and the relative pressure anisotropy is generally non-zero, (except for the special case where the model degenerates to Schwarzschild-(anti)de Sitter spacetime).

TL;DR: The spectral dimension is a scale-dependent number associated with both geometries and field theories that has recently attracted much attention, driven largely, though not exclusively, by investigations of causal dynamical triangulations and Ho\ifmmode \check{r}else \v{r}\fi{}ava gravity as possible candidates for quantum gravity as discussed by the authors.