Particle dynamics and quasi-periodic oscillations around quantum Oppenheimer-Snyder de Sitter black hole
Abstract
In this paper, we investigate the dynamics of neutral test particles in the background of a non-rotating quantum Oppenheimer–Snyder black hole (BH) with a positive cosmological constant, an effective spacetime derived from loop quantum gravity corrections to classical gravitational collapse. The spacetime metric is characterized by a quantum correction parameter β , mass M , and cosmological constant Λ , which together modify the near-horizon geometry and yield a minimum BH mass threshold absent in classical GR. We analyze the effective potential governing particle motion and demonstrate how β influences the stability of orbits, the location of the innermost stable circular orbits (ISCOs), and the associated conserved quantities. Our results show that increasing quantum corrections shifts the ISCOs radius inward, allowing stable orbits closer to the horizon, while decreasing the energy and angular momentum of circular trajectories. We provide the constraints on the parameters involved by using the shadow radius. Perturbations around circular motion are studied to derive epicyclic frequencies, which describe small radial and vertical oscillations and are central to quasi-periodic oscillations (QPOs) models observed in accreting compact objects. We compute these oscillatory frequencies as measured by both local and distant observers and explore the periastron precession frequency as a function of the quantum parameter. In addition, the analysis reveals that quantum effects significantly modify the profiles of epicyclic frequencies and precession, potentially leaving observable imprints in the timing properties of astrophysical accretion systems.