Mini-Superspace Hamiltonian Dynamics and Canonical Quantization of Bumblebee Cosmology

Abstract

The work presents a canonical Hamiltonian system in a classical scenario and further extend the analysis to a quantum mechanical framework for a homogeneous and isotropic universe governed by Bumblebee gravity, in which spontaneous Lorentz symmetry breaking is triggered by a vector field acquiring a vacuum expectation value (VEV). Starting from the full four-dimensional covariant action, the derivation has been carried out for the one-dimensional mini-superspace Lagrangian density for a flat Friedmann-Lemaître-Robertson-Walker (FLRW) background with a purely temporal bumblebee field configuration. Further, the work focuses on to construct the classical Hamiltonian system through a canonical Legendre transformation, identifying the lapse function $N(t)$ as a Lagrange multiplier enforcing a primary Hamiltonian constraint. Apart form that, the conservation of phase-space volume via Liouville's theorem, locate and classify the critical points of the resulting dynamical system, and examine the stability of the Lorentz-violating vacuum has been carried to test the classical Hamiltonian system in the work. Furthermore, the modified first and second Friedmann equations and discuss the resulting time-dependence of the effective gravitational coupling, illustrating the results with numerical phase-space has been discussed in this work. Finally, the work extended to construct the Wheeler-DeWitt equation through the canonical quantization and obtain the approximate solutions in the deep-quantum ($a\to0$) and near-vacuum regimes for it.