Analytic and numerical constraints on QPOs in EHT and XRB sources using quantum-corrected black holes

Abstract

This investigation examines quasi-periodic oscillations (QPOs) in two quantum-corrected black hole (BH) spacetimes that preserve general covariance while incorporating quantum gravitational effects through a dimensionless parameter ζ. We combine analytical derivations of epicyclic frequencies with comprehensive numerical simulations of Bondi-Hoyle-Lyttleton (BHL) accretion to explore how quantum corrections manifest in observable astrophysical phenomena. Using a fiducial BH mass of $M=10M_{\odot }$ representative of stellar-mass X-ray binaries, we demonstrate that the two models exhibit fundamentally different behaviors: Model-I modifies both temporal and radial metric components, leading to innermost stable circular orbit migration proportional to ζ⁴ and dramatic stagnation point evolution from 27M to 5M as quantum corrections strengthen. Model-II preserves the classical temporal component while altering only spatial geometry, maintaining constant stagnation points and stable cavity structures throughout the parameter range. Our numerical simulations reveal distinct QPO generation mechanisms, with Model-I showing systematic frequency evolution and cavity shrinkage that suppresses oscillations for ζ ≥ 3M, while Model-II maintains stable low-frequency modes up to ζ ≥ 5M. Power spectral density analyzes demonstrate characteristic frequency ratios (3: 2, 2: 1, 5: 3) consistent with observations from X-ray binaries, providing specific targets for discriminating between quantum correction scenarios. The hydrodynamically derived constraints (ζ ≲ 4M) show remarkable agreement with independent Event Horizon Telescope limits for M87* and Sgr A*, validating our theoretical framework through multiple observational channels. These results establish QPO frequency analysis as a probe for detecting quantum gravitational effects in astrophysical BHs and demonstrate the complementary nature of timing and imaging observations in constraining fundamental physics.