Probing quantum corrected Kazakov–Solodukhin black holes through QPOs and thin accretion disks

Abstract We investigate the geodesic motion and accretion disc signatures of the Kazakov–Solodukhin (KS) quantum-corrected black hole. This regular solution incorporates leading-order quantum effects into the Schwarzschild geometry. For massive test particles, we compute the innermost stable circular orbit (ISCO) together with the corresponding energy and angular momentum. We also derive the fundamental frequencies of radial and vertical oscillations and apply them to standard models of quasi-periodic oscillations (QPOs). In addition, we examine thin accretion discs using the Novikov–Thorne framework, focusing on the flux, temperature distribution, and spectral luminosity. Compared with the Schwarzschild case, the KS spacetime shows apparent differences in ISCO location, oscillation frequencies, and disc emission profiles, all of which are governed by the deformation parameter. By comparing our models with current observational QPO data, we show that this spherically symmetric spacetime cannot fit the data better than the Schwarzschild metric. Additionally, although the KS quantum-corrected black hole predicts distinct spectral properties, we cannot resolve the degeneracy between the quantum correction parameter and other astrophysical parameters (such as mass accretion rate, inclination angle, and black hole spin).