Phenomenology of Schwarzschild-like black holes with a generalized Compton wavelength

We investigate the influence of the generalized Compton wavelength (GCW), emerging from a three-dimensional dynamical quantum vacuum (3D DQV) on Schwarzschild-like black hole spacetimes. The GCW modifies the classical geometry through a deformation parameter ɛ, encoding quantum gravitational backreaction. We derive exact analytical expressions for the black hole shadow radius, photon sphere, and weak deflection angle, incorporating higher-order corrections and finite-distance effects of a black hole with generalized Compton effect (BHGCE). Using Event Horizon Telescope (EHT) data, constraints on ɛ are obtained: ɛ∈[−2.572,0.336] for Sgr. A* and ɛ∈[−2.070,0.620] for M87*, both consistent with general relativity yet allowing moderate deviations. Weak lensing analyses via the Keeton–Petters and Gauss–Bonnet formalisms further constrain ɛ≈0.061, aligning with solar system bounds. We compute the modified Hawking temperature, showing that positive ɛ suppresses black hole evaporation. Quasinormal mode frequencies in the eikonal limit are also derived, demonstrating that both the oscillation frequency and damping rate shift under GCW-induced corrections. Additionally, the gravitational redshift and scalar perturbation waveform exhibit deformations sensitive to ɛ. Our results highlight the GCW framework as a phenomenologically viable semiclassical model, offering testable predictions for upcoming gravitational wave and VLBI observations.