11 citations · 26 across the 8 of their papers we have counts for
9 papers · 1 filter
Generalized Unimodular Gravity and Cosmological Perturbations
Júlio C. Fabris, Alexander Yu. Kamenshchik
The generalized unimodular theory is revisited and its consequence for cosmology is discussed. The usual matter components of the universe are obtained in a pure geometric way. Thi…
On gravitational collapse and integrable singularities
Roberto Casadio, Andrea Giusti, Alexander Kamenshchik +1
Schwarzschild black holes are expected to emerge as the end states of the classical gravitational collapse from non-singular configurations. After integrable curvature singularitie…
Cosmological Singularities and Quantum Particles
Samuel W. P. Oliveira, Alexander Yu. Kamenshchik
We study if there is an opportunity to describe quantum particles in the vicinity of three types of cosmological singularities, big bang-big crunch, big rip and big brake. Writing…
On Schwarzschild black hole singularity formation
Jorge Ovalle, Roberto Casadio, Alexander Kamenshchik
We examine whether the Schwarzschild black hole can emerge as the continuous end state of gravitational collapse from a non-singular configuration. Employing a time dependent exten…
Regular Schwarzschild black holes and cosmological models
Roberto Casadio, Alexander Kamenshchik, Jorge Ovalle
We study regular Schwarzschild black holes in General Relativity as an alternative to the singular counterpart. We analyze two types of solutions which are completely parameterised…
Again About Singularity Crossing In Gravitation And Cosmology
Alexander Kamenshchik
We discuss the problem of singularity crossing in isotropic and anisotropic universes. We study at which conditions singularities can disappear in quantum cosmology and how quantum…
Cosmology from Schwarzschild black hole revisited
Roberto Casadio, Alexander Kamenshchik, Jorge Ovalle
We study cosmological models based on the interior of the revisited Schwarzschild black hole recently reported in [Phys.~Rev.~D{\bf 109} (2024) 104032]. We find that these solution…
Relaxation of first-class constraints and the quantization of gauge theories: from "matter without matter" to the reappearance of time in quantum gravity
Roberto Casadio, Leonardo Chataignier, Alexander Yu. Kamenshchik +3
We make a conceptual overview of a particular approach to the initial-value problem in canonical gauge theories. We stress how the first-class phase-space constraints may be relaxe…
From black hole mimickers to black holes
Roberto Casadio, Alexander Kamenshchik, Jorge Ovalle
We present a simple analytical model for studying the collapse of an ultracompact stellar object (regular black hole mimicker with infinite redshift surface) to form a (integrable)…