Circular orbits and quasiperiodic oscillations near charged black holes in Verlinde gravity
Аннотация
We investigate the dynamics of charged black holes within the framework of Verlinde's emergent gravity, focusing on their implications for circular orbits and quasiperiodic oscillations (QPOs). Verlinde’s theory modifies the traditional picture of gravitation by introducing entropy-based corrections, interpreted as effects from apparent dark matter. In this context, we construct regular black hole solutions characterized by nonsingular spacetime geometries and analyze how these modifications affect geodesic motion. We derive the effective potential for neutral test particles, identify conditions for circular stability, and compute the innermost stable circular orbit (ISCO). The fundamental frequencies associated with geodesic motion—Keplerian, radial, and vertical epicyclic frequencies—are calculated and compared across different parameter regimes. We further examine how these frequencies translate into observable quasiperiodic oscillations by applying resonance models to fit the twin-peak QPO data from the microquasar GRS 1915+105. The study reveals that the entropy-induced corrections in Verlinde gravity significantly influence the ISCO radius and frequency structure. Our results suggest that timing signals in X-ray binaries offer promising observational tests for modified gravity models like Verlinde's.