Degree

Doctor of Philosophy (PhD)

Department

Department of Physics & Astronomy

Document Type

Dissertation

Abstract

Loop quantum gravity (LQG) techniques applied to symmetry-reduced spacetimes generically resolve the big bang and black hole interior singularities of classical general relativity. In loop quantum cosmology (LQC), the big bang singularity is replaced with a non-singular quantum bounce connecting the pre-bounce contracting and post-bounce expanding branches, while the black hole interior singularity is, in general, replaced with a smooth finite transition surface yielding a black-hole-to-white-hole transition. In this dissertation, we investigate the implications of quantum gravitational singularity resolution for the physics of the very early universe and black holes within the LQG/LQC framework. In the first part, we show that singularity resolution sheds light on several long-standing primordial cosmological puzzles. It provides a non-singular completion of the tunneling wave function proposal for the boundary conditions of the universe, and, together with dissipative particle production, it alleviates the onset problem of inflation in a spatially closed universe. Furthermore, we find that the quantum gravitational isotropization mechanism comes at a steep price---the lack of an exit to a classical universe---and even at this price, the mechanism is not generic. In addition, we observe that the bounce acts as a seesaw mechanism for primordial magnetic fields, amplifying or suppressing them depending on their pre-bounce strength, and that different regularization ambiguities in isotropic LQC lead to distinct observational effects in the cosmic microwave background. We also compute Krylov complexity in the solvable LQC model, finding that it remains finite at the bounce, in contrast to the Wheeler-DeWitt theory, and paving the way for characterizing quantum chaos in quantum cosmology. In the second part, we investigate the linear static response of loop quantum black holes to an external tidal field. We demonstrate that the tidal Love numbers of these black holes are generally non-zero, in contrast to their classical counterparts, manifesting as novel perturbative quantum hair with profound theoretical and phenomenological implications.

Date

7-13-2026

Committee Chair

Parampreet Singh

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

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