161 citations · 1.1k across the 23 of their papers we have counts for
5 papers · 1 filter
Does the quantum mechanical wave function exist?
Claus Kiefer
I address the question whether the wave function in quantum theory exists as a real (ontic) quantity or not. For this purpose, I discuss the essentials of the quantum formalism and…
Singularity avoidance for collapsing quantum dust in the Lemaitre-Tolman-Bondi model
Claus Kiefer, Tim Schmitz
We investigate the fate of the classical singularity in a collapsing dust cloud. For this purpose, we quantize the marginally bound Lemaitre-Tolman-Bondi model for spherically-symm…
Phantom singularities and their quantum fate: general relativity and beyond
Mariam Bouhmadi-López, Claus Kiefer, Prado Martín-Moruno
Cosmological observations allow the possibility that dark energy is caused by phantom fields. These fields typically lead to the occurrence of singularities in the late Universe. W…
Singularity avoidance in Bianchi I quantum cosmology
Claus Kiefer, Nick Kwidzinski, Dennis Piontek
We extend recent discussions of singularity avoidance in quantum gravity from isotropic to anisotropic cosmological models. The investigation is done in the framework of quantum ge…
Quantum-gravity effects for excited states of inflationary perturbations
David Brizuela, Claus Kiefer, Manuel Kraemer +1
We generalize former findings regarding quantum-gravitational corrections arising from a canonical quantization of a perturbed FLRW universe during inflation by considering an init…